MEAN AGE OF MOTHER AT FIRST LIVE BIRTH

Method & caveats. Mean (not median) age at first live birth, all races and origins; the arithmetic average computed directly from the frequency of first births by age of mother. Edition list, newest wins on overlap: NVSR 51-1 Table 1 (1970–2000); NVSR 74-9 Table 1 (2016–2023, identical to the 2024 edition on every overlapping year, so no revision); NVSR 75-2 Table 4 (2010–2024). 2001–2009 could not be recovered: the only archived source covering that span, NCHS Data Brief 232, reports the trend only as a line chart plus three narrative anchor values (2000, 2009, 2014), not a machine-readable annual table; no value was read off the chart or interpolated. The four reports are archived in data/nchs/ with their hashes recorded in READ.md. Breaks: 2001–2009 gap: Data Brief 232 for that window is chart-only, not machine-readable. Reports before 2016 do not carry the same race/Hispanic-origin breakout as 2016 onward.