Yeah they're percents, but I think the numbers are more different than 70M vs 69M.
Taking an average of US Census 1960 + 1970 (179,323,175 + 203,302,031 / 2 = 191,312,603) * .43 of population = ~82M
vs
2000 + 2010 (281,421,906 + 308,745,538 / 2 = 295,083,722) * .23 of pop = ~68M
Averages...