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<article article-type="research-article" dtd-version="2.3" xml:lang="EN" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">
<front>
<journal-meta>
<journal-id journal-id-type="publisher-id">Front. Big Data</journal-id>
<journal-title>Frontiers in Big Data</journal-title>
<abbrev-journal-title abbrev-type="pubmed">Front. Big Data</abbrev-journal-title>
<issn pub-type="epub">2624-909X</issn>
<publisher>
<publisher-name>Frontiers Media S.A.</publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="publisher-id">802256</article-id>
<article-id pub-id-type="doi">10.3389/fdata.2021.802256</article-id>
<article-categories>
<subj-group subj-group-type="heading">
<subject>Big Data</subject>
<subj-group>
<subject>Data Report</subject>
</subj-group>
</subj-group>
</article-categories>
<title-group>
<article-title>Social Security Number Holders in the United&#x20;States, 1909-2019</article-title>
<alt-title alt-title-type="left-running-head">Ogihara</alt-title>
<alt-title alt-title-type="right-running-head">Social Security Number Holders</alt-title>
</title-group>
<contrib-group>
<contrib contrib-type="author" corresp="yes">
<name>
<surname>Ogihara</surname>
<given-names>Yuji</given-names>
</name>
<xref ref-type="corresp" rid="c001">&#x2a;</xref>
<uri xlink:href="https://loop.frontiersin.org/people/121463/overview"/>
</contrib>
</contrib-group>
<aff>Faculty of Science Division II, Tokyo University of Science, <addr-line>Tokyo</addr-line>, <country>Japan</country>
</aff>
<author-notes>
<fn fn-type="edited-by">
<p>
<bold>Edited by:</bold> <ext-link ext-link-type="uri" xlink:href="https://loop.frontiersin.org/people/1104811/overview">Kathiravan Srinivasan</ext-link>, VIT University, India</p>
</fn>
<fn fn-type="edited-by">
<p>
<bold>Reviewed by:</bold> <ext-link ext-link-type="uri" xlink:href="https://loop.frontiersin.org/people/1535929/overview">Surya Krishnamurthy</ext-link>, iQGateway, India</p>
<p>
<ext-link ext-link-type="uri" xlink:href="https://loop.frontiersin.org/people/1536709/overview">Jayalakshmi Murugan</ext-link>, National Engineering College, Anna University, India</p>
</fn>
<corresp id="c001">&#x2a;Correspondence: Yuji Ogihara, <email>yogihara@rs.tus.ac.jp</email>
</corresp>
<fn fn-type="other">
<p>This article was submitted to Medicine and Public Health, a section of the journal Frontiers in Big&#x20;Data</p>
</fn>
</author-notes>
<pub-date pub-type="epub">
<day>14</day>
<month>12</month>
<year>2021</year>
</pub-date>
<pub-date pub-type="collection">
<year>2021</year>
</pub-date>
<volume>4</volume>
<elocation-id>802256</elocation-id>
<history>
<date date-type="received">
<day>26</day>
<month>10</month>
<year>2021</year>
</date>
<date date-type="accepted">
<day>09</day>
<month>11</month>
<year>2021</year>
</date>
</history>
<permissions>
<copyright-statement>Copyright &#xa9; 2021 Ogihara.</copyright-statement>
<copyright-year>2021</copyright-year>
<copyright-holder>Ogihara</copyright-holder>
<license xlink:href="http://creativecommons.org/licenses/by/4.0/">
<p>This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these&#x20;terms.</p>
</license>
</permissions>
<abstract>
<p>Currently, a social security number (SSN) is held by almost every legal resident of the United States and works as an important numbering system. However, this was not the case in the early years of the Social Security program and historical changes in SSN holder rates had not been examined sufficiently. It is important to understand the changes in health policies and situations. Thus, the present article examined historical changes in the rates of SSN holders in the United States between 1909 and 2019. Analyses demonstrated that the rates clearly increased. Specifically, in Phase 1 (1909-1919), the rates were low in the early period, but they increased markedly. In Phase 2 (1919-1952), the rates continued to increase gradually. In Phase 3 (1952-2019), the rates were almost 100% and reached saturation. This basic information leads to a better understanding of the health policies and situations, contributing to medical and social science research.</p>
</abstract>
<kwd-group>
<kwd>social security number</kwd>
<kwd>historical change</kwd>
<kwd>the United&#x20;States</kwd>
<kwd>health policy</kwd>
<kwd>SSN</kwd>
<kwd>Social Security Administration</kwd>
<kwd>Enumeration at Birth program</kwd>
<kwd>open data</kwd>
</kwd-group>
</article-meta>
</front>
<body>
<sec id="s1">
<title>Introduction</title>
<p>Currently, a social security number (SSN) is held by almost every legal resident of the United&#x20;States and&#x20;works as an important numbering system [for reviews, see <xref ref-type="bibr" rid="B3">Puckett (2009)</xref>; <xref ref-type="bibr" rid="B2">Puckett (2010)</xref>].&#x20;Originally, the purpose of the SSN was to track an individual worker&#x2019;s&#x20;financial information, which is necessary to work domestically. Later, because of its efficiency, the SSN gained various widespread uses, such as health insurance, medical&#x20;assistance, and supplemental security income. Finally, it has become a national&#x20;identifier, and consequently, the most commonly used numbering system in the United&#x20;States.</p>
<p>Today, nearly everyone in the United&#x20;States has an SSN, but this was not the case in the early&#x20;years of the Social Security program (<xref ref-type="bibr" rid="B5">Tacker, 1972</xref>). The SSN was created in 1936 by the&#x20;Social Security Administration (SSA; originally Social Security Board until 1946) under the&#x20;Social Security Act for the purpose of tracking the earnings histories of certain workers&#x20;in&#x20;the&#x20;United States. Thus, people who died prior to 1936 or did not work in a job covered by the&#x20;program were not issued an SSN. Over time, more occupations became covered&#x20;by the&#x20;program, and the use of the SSN expanded significantly, leading to an increasing number of people obtaining an SSN. After 1987, it became common to request&#x20;an SSN when a baby was born as a part of the state&#x2019;s birth registration (Enumeration at Birth program). Presently, over 90% of parents use this program (<xref ref-type="bibr" rid="B3">Puckett, 2009</xref>).</p>
<p>However, historical changes in SSN holder rates had not been examined sufficiently<xref ref-type="fn" rid="fn1">
<sup>1</sup>
</xref>. They&#x20;provide important and fundamental information for medical and social science research. For example, it is useful to understand the changes in health policies and situations in the United&#x20;States, which contributes to research in medicine and social sciences. Therefore, the present article examined the historical changes in the rates of SSN holders.</p>
</sec>
<sec sec-type="materials|methods" id="s2">
<title>Method</title>
<p>The rates of SSN holders in the United&#x20;States were calculated as the number of SSN holders&#x20;divided by the number of live births each year. The raw data analyzed in this study are available online (<ext-link ext-link-type="uri" xlink:href="https://doi.org/10.17605/OSF.IO/DSRG9">https://doi.org/10.17605/OSF.IO/DSRG9</ext-link>).</p>
<sec id="s2-1">
<title>Number of SSN Holders</title>
<p>The numbers of SSN holders born in the United&#x20;States between&#x20;1909 and 2019 by year of birth are summarized in <xref ref-type="fig" rid="F1">Figure&#x20;1</xref>. The data are from <xref ref-type="bibr" rid="B4">Social Security Administration (2020)</xref>
<xref ref-type="fn" rid="fn2">
<sup>2</sup>
</xref>.</p>
<fig id="F1" position="float">
<label>FIGURE 1</label>
<caption>
<p>The numbers of SSN holders born in the United&#x20;States and live births between 1909 and 2019.</p>
</caption>
<graphic xlink:href="fdata-04-802256-g001.tif"/>
</fig>
<p>It should be noted that the years indicate the years of birth&#x20;of SSN holders, not the years when people acquired&#x20;SSNs. Thus, the values indicate the rates of SSN holders among&#x20;people born in a given year as of December 2020.</p>
</sec>
<sec id="s2-2">
<title>Number of Live Births</title>
<p>The numbers of live births in the United&#x20;States between 1909 and 2019 are indicated in <xref ref-type="fig" rid="F1">Figure&#x20;1</xref>. The data are from the Centers for Disease Control and Prevention (CDC). Specifically, the numbers between 1909 and 2003 are from the Vital Statistics of the United&#x20;States, 2003 (<xref ref-type="bibr" rid="B7">Centers for Disease Control and Prevention, 2003</xref>), those between 2004 and 2015 are from the National Vital Statistics Report, 2017 (<xref ref-type="bibr" rid="B6">Centers for Disease Control and Prevention, 2017</xref>), and those between 2016 and 2019 are from the National Vital Statistics Report, 2021 (<xref ref-type="bibr" rid="B1">Centers for Disease Control and Prevention, 2021</xref>).</p>
</sec>
</sec>
<sec id="s2-3">
<title>The Three Phases</title>
<p>The historical changes in the rates of SSN holders in the United&#x20;States between 1909 and 2019 are summarized in&#x20;<xref ref-type="fig" rid="F2">Figure&#x20;2</xref>. Overall, the rates increased markedly over time. These changes can be divided into three phases below.</p>
<fig id="F2" position="float">
<label>FIGURE 2</label>
<caption>
<p>The historical changes in the rates of SSN holders in the United&#x20;States between 1909 and&#x20;2019.</p>
</caption>
<graphic xlink:href="fdata-04-802256-g002.tif"/>
</fig>
<sec id="s2-4">
<title>Phase 1 (1909-1919): Remarkable Increase</title>
<p>In the early periods, the rates were low. In 1909, the rate was&#x20;approximately 20% (20.05%); only one of five people had an&#x20;SSN.</p>
<p>However, the rates increased markedly until 1919. In 1915, the rate exceeded 50% (64.24%) and in 1919, it reached approximately 80% (79.93%).</p>
</sec>
<sec id="s2-5">
<title>Phase 2 (1919-1952): Gradual Increase</title>
<p>In 1922, the rate was over 80% (82.33%) and continued to&#x20;increase gradually. This increase was not as steep as that in Phase 1, but it steadily continued to increase until&#x20;1952.</p>
</sec>
<sec id="s2-6">
<title>Phase 3 (1952-2019): Saturation (Almost 100% Continued)</title>
<p>In 1952, the rate was over 99% (99.14%), and after that, the rates were almost 100%<xref ref-type="fn" rid="fn3">
<sup>3</sup>
</xref>. In this phase, the rates continued to be approximately 100%; almost all who were born in a given year acquired an&#x20;SSN.</p>
</sec>
</sec>
<sec sec-type="conclusion" id="s3">
<title>Conclusion</title>
<p>The present article examined historical changes in the rates of SSN holders in the United&#x20;States between 1909 and 2019. Analyses demonstrated that the rates clearly increased. Specifically, the temporal changes can be explained in the three phases. In Phase 1 (1909-1919), the rates were low in the early period, but they increased markedly. In Phase 2 (1919-1952), the rates continued to increase gradually. In Phase 3 (1952-2019), the rates were almost 100% and reached saturation.</p>
<p>Although the SSN has been one of the most important numbering systems in the United&#x20;States [e.g., <xref ref-type="bibr" rid="B3">Puckett (2009)</xref>;&#x20;<xref ref-type="bibr" rid="B2">Puckett (2010)</xref>], its historical changes in prevalence had not been sufficiently examined. The basic information that&#x20;the present article provides leads to a better understanding of the health policies and situations in the United&#x20;States, contributing to medical and social science research.</p>
</sec>
</body>
<back>
<sec id="s4">
<title>Data Availability Statement</title>
<p>The datasets presented in this study can be found in online&#x20;repositories. The names of the repository/repositories and&#x20;accession number(s) can be found below: Open Science&#x20;Framework (<ext-link ext-link-type="uri" xlink:href="https://doi.org/10.17605/OSF.IO/DSRG9">https://doi.org/10.17605/OSF.IO/DSRG9</ext-link>).</p>
</sec>
<sec id="s5">
<title>Author Contributions</title>
<p>The author confirms being the sole contributor of this work and approved it for publication.</p>
</sec>
<sec sec-type="COI-statement" id="s6">
<title>Conflict of Interest</title>
<p>The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.</p>
</sec>
<sec sec-type="disclaimer" id="s7">
<title>Publisher&#x2019;s Note</title>
<p>All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.</p>
</sec>
<sec id="s8">
<title>Supplementary Material</title>
<p>The Supplementary Material for this article can be found online at: <ext-link ext-link-type="uri" xlink:href="https://www.frontiersin.org/articles/10.3389/fdata.2021.802256/full#supplementary-material">https://www.frontiersin.org/articles/10.3389/fdata.2021.802256/full&#x23;supplementary-material</ext-link>
</p>
<supplementary-material xlink:href="DataSheet1.docx" id="SM1" mimetype="application/docx" xmlns:xlink="http://www.w3.org/1999/xlink"/>
</sec>
<fn-group>
<fn id="fn1">
<label>1</label>
<p> I asked the SSA in February 2021 whether they had data on the SSN holder rates over time, and they replied that they did not. Thus, I calculate, summarize, and report them&#x20;here.</p>
</fn>
<fn id="fn2">
<label>2</label>
<p> The original data also include the numbers of SSN holders born in the United&#x20;States between 1880 and 1908, which are summarized in <xref ref-type="sec" rid="s8">Supplementary Figure&#x20;S1</xref>.</p>
</fn>
<fn id="fn3">
<label>3</label>
<p> Some percentages were slightly over 100%. This is because the numbers of live births were estimated by a sampling of birth [for details, see <xref ref-type="bibr" rid="B7">Centers for Disease Control and Prevention (2003)</xref>].</p>
</fn>
</fn-group>
<ref-list>
<title>References</title>
<ref id="B7">
<citation citation-type="book">
<collab>Centers for Disease Control and Prevention</collab> (<year>2003</year>). <source>Vital Statistics of the United&#x20;States, 2003</source>. <publisher-name>Natality</publisher-name>. <comment>Available at: <ext-link ext-link-type="uri" xlink:href="https://www.cdc.gov/nchs/products/vsus/vsus_1980_2003.htm">https://www.cdc.gov/nchs/products/vsus/vsus_1980_2003.htm</ext-link>
</comment>. </citation>
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<citation citation-type="book">
<collab>Centers for Disease Control and Prevention</collab> (<year>2017</year>). <source>Births: Final Data for 2015. Natl. Vital Stat. Rep</source>. <comment>66 (1), 1&#x2013;70. Available at: <ext-link ext-link-type="uri" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://www.cdc.gov/nchs/products/nvsr.htm">https://www.cdc.gov/nchs/products/nvsr.htm</ext-link>
</comment>. </citation>
</ref>
<ref id="B1">
<citation citation-type="book">
<collab>Centers for Disease Control and Prevention</collab> (<year>2021</year>). <source>Births: Final Data for 2019. Natl. Vital Stat. Rep</source>. <comment>70 (2), 1&#x2013;51. Available at: <ext-link ext-link-type="uri" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://www.cdc.gov/nchs/products/nvsr.htm">https://www.cdc.gov/nchs/products/nvsr.htm</ext-link>
</comment>. </citation>
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<ref id="B3">
<citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname>Puckett</surname>
<given-names>C.</given-names>
</name>
</person-group> (<year>2009</year>). <article-title>The story of the Social Security Number</article-title>. <source>Soc. Secur Bull.</source> <volume>69</volume>, <fpage>55</fpage>&#x2013;<lpage>74</lpage>. </citation>
</ref>
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<citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname>Puckett</surname>
<given-names>C.</given-names>
</name>
</person-group> (<year>2010</year>). <article-title>Administering Social Security: Challenges Yesterday and Today</article-title>. <source>Soc. Secur Bull.</source> <volume>70</volume>, <fpage>27</fpage>&#x2013;<lpage>78</lpage>. </citation>
</ref>
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<citation citation-type="web">
<collab>Social Security Administration</collab> (<year>2020</year>). <article-title>Get Ready for Baby</article-title>. <comment>Available at: <ext-link ext-link-type="uri" xlink:href="https://www.ssa.gov/oact/babynames/index.html">https://www.ssa.gov/oact/babynames/index.html</ext-link>
</comment>. </citation>
</ref>
<ref id="B5">
<citation citation-type="journal">
<person-group person-group-type="author">
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<surname>Tacker</surname>
<given-names>H. R.</given-names>
</name>
</person-group> (<year>1972</year>). <article-title>Social Security Numbers Issued, 1937-71</article-title>. <source>Soc. Security Bull.</source> <volume>35</volume>, <fpage>30</fpage>&#x2013;<lpage>32</lpage>. </citation>
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</ref-list>
</back>
</article>