Whatever you think the answer is to the question posed in the title, I'd guess that that your estimate is way off. Mine sure was as I was seduced by a promiscuous factoid.  Enjoy!

How Many People Have Ever Lived On Earth? 108 Billion
Year Population Births per 1,000 Births Between Benchmarks
50,000 B.C. 2 - -
8000 B.C. 5,000,000 80 1,137,789,769
1 A.D. 300,000,000 80 46,025,332,354
1200 450,000,000 60 26,591,343,000
1650 500,000,000 60 12,782,002,453
1750 795,000,000 50 3,171,931,513
1850 1,265,000,000 40 4,046,240,009
1900 1,656,000,000 40 2,900,237,856
1950 2,516,000,000 31-38 3,390,198,215
1995 5,760,000,000 31 5,427,305,000
2011 6,215,000,000 23 2,130,327,622

NUMBER WHO HAVE EVER BEEN BORN 107,602,707,791
World population in mid-2011 6,987,000,000
Percent of those ever born who are living in 2011 6.5
Source: Population Reference Bureau estimates.