Not especially. January 17 is less common than most dates in these historical U.S. records, but it is not among the rarest. It ranks #258 of 366 dates by total births from 1994 through 2014. Rank #1 means most common.
January 17 had 230,038 births across 21 occurrences, or 10,954 births per occurrence. That is 0.268% of the 85,712,738-birth sample, or about 1 in 373 recorded births.
Within January, January 17 ranks tenth of 31 dates.
Five of its 21 occurrences fell on a Saturday or Sunday. The average across all dates is 6.0. Weekend days have fewer recorded births, so this calendar mix can raise its total. This comes from the calendar in these years, not from the date itself.
What happens when January 17 is Martin Luther King Jr. Day?
Martin Luther King Jr. Day falls on the third Monday in January. In SSA 2000–2014, that Monday was January 17 in 2000, 2005, and 2011.
In those three years, January 17 had 4.2% fewer births than nearby Mondays. In the other 12 years, it had 0.1% more births than its controls.
Three occurrences are a small group. This difference is much smaller than the Memorial Day and Thanksgiving differences in these records. It does not establish a holiday pattern.
Across all 15 years, the primary comparison gives -0.7%. With only the 7-day or only the 14-day controls, the results are -1.3% and -0.2%.
Baseline ranks use historical U.S. CDC/NCHS and SSA records, 1994–2014. The percentage differences use SSA 2000–2014 alone. Each table row compares January 17 with controls from the same year.
| Comparison | Years | Control observations | Difference |
|---|---|---|---|
| 7 and 14 days, holidays excluded (primary) | 15 | 60 | -0.7% |
| 7 days only | 15 | 30 | -1.3% |
| 14 days only | 15 | 30 | -0.2% |
| 7 and 14 days, no holiday exclusions | 15 | 60 | -0.7% |
| Martin Luther King Jr. Day years only | 3 | 12 | -4.2% |
| Other years only | 12 | 48 | +0.1% |
How were the comparison dates chosen?
The primary controls are January 3, January 10, January 24, and January 31 in the same year. Each is 7 or 14 days from January 17, so it falls on the same weekday.
None of these controls fell on an excluded holiday. We exclude holidays under the standard observed federal holiday rules. We also exclude Christmas Eve, December 26, and the Friday after Thanksgiving.
By five-year period, the primary differences are -1.3% for 2000–2004, -1.0% for 2005–2009, and +0.2% for 2010–2014.
To combine the years, we divide the summed target births by the summed annual control means. Then we subtract one and multiply by 100. The result is not an average of annual percentages.
Is the January 17 rank stable over time?
Yes. We ranked 365 recurring dates by SSA births in each five-year period. January 17 placed #226 in 2000–2004, #196 in 2005–2009, and #222 in 2010–2014. The three ranks span 30 places.
That span is narrow. The median span for all 365 recurring dates is 159 places.
These ranks use raw birth counts. The ranking-stability study also compares annual shares and weekday-relative scores for every date.
Sources and limits
Baseline totals and ranks use FiveThirtyEight’s pinned U.S. birth files. We use CDC/NCHS for 1994–1999 and SSA for 2000–2014, so no year comes from both sources. Annual comparisons use SSA alone.
The source series have different administrative coverage. These records do not describe worldwide births, everyone alive today, or current birth rates.
The daily totals do not record delivery methods or scheduling decisions. Weekday matching does not remove every seasonal difference. Federal holiday rules identify calendar dates, not hospital schedules.
Use the January guide for the full month ranking. See also the January 2 and January 8 studies.
The holiday birth study compares four fixed-date federal holidays.
The methodology explains ranks and shares. Use the birthday checker to compare another date.