This page I found ( https://iter.ca/post/1875-epoch/ https://iter.ca/post/1875-epoch/ ) had a link to some data from SSA: https://www.ssa.gov/policy/docs/ssb/v7

This page I found ( https://iter.ca/post/1875-epoch/ https://iter.ca/post/1875-epoch/ ) had a link to some data from SSA: https://www.ssa.gov/policy/docs/ssb/v71n4/v71n4p33.html https://www.ssa.gov/policy/docs/ssb/v71n4/v71n4p33.html , and the "Individuals by YOB" section does indeed not show anything special about 1875 (and has people from before then).