Year Percent 1950 10.87068 1955 11.13747 1960 10.92854 1965 11.07576 1970 11.25652 1975 11.53554 1980 12.42883 1985 12.61624 1990 14.48244 1995 14.1562 2000 14.12554 2005 14.7733 2010 16.60396 2015 18.85162 2020 21.22703 2025 23.20219 2030 24.35848 2035 24.9212 2040 25.2886 2045 25.82867 2050 26.65511 2055 27.66673 2060 28.40898 2065 29.10948 2070 29.83204 2075 30.22645 2080 30.67919 2085 31.17501 2090 31.6564 2095 32.12002 2100 32.55681