Adding to your point: The US population today is approximately double what it was in 1957-58. 332M today 151M in 1950 179M in 1960. So if growing at an even rate during the decade, that would make 1957 approx. 170M
1957 - 171,984,130. 1958 - 174,881,904
172,000.00 x 2 = 344,000.00
As said, "approximately double."