Year Percent 1950 11.09712 1955 11.96153 1960 13.07872 1965 13.96021 1970 14.55036 1975 15.18542 1980 15.82428 1985 16.3677 1990 18.33223 1995 17.47158 2000 16.91598 2005 17.67622 2010 19.18109 2015 20.2417 2020 21.86629 2025 23.45259 2030 25.27931 2035 26.62905 2040 27.19921 2045 27.80936 2050 28.52132 2055 29.29056 2060 29.96377 2065 30.43598 2070 31.07365 2075 31.57145 2080 32.20198 2085 32.86167 2090 33.49554 2095 34.10004 2100 34.6743