year,people,pct_labor_force
1840,9012000,69
1850,11680000,64
1860,15141000,58
1870,18373000,53
1880,22981000,49
1890,29414000,43
1900,29414000,38
1910,32077000,31
1920,31614269,27
1930,30455350,21
1940,30840000,18
1950,25058000,12.2
1960,15635000,8.3
1970,9712000,4.6
1980,6051000,3.4
1990,2987552,2.6