population (millions)
1800-1950
lower
estimate
upper
estimate
1800 813 1125
1850 1128 1402
1900 1550 1762
1910 1750
1920 1860
1930 2070
1940 2300
1950 2400 2556
 growth factor
1800-1950
       2.95       2.27  
average compound
annual rate of growth
0.724% 0.549%
years to double           96              127  
double             2                 2