Year Percent 1950 15.71406 1955 15.67414 1960 15.99027 1965 15.42288 1970 15.71834 1975 15.71907 1980 16.4112 1985 17.32595 1990 18.19953 1995 20.62208 2000 22.94829 2005 26.07223 2010 28.87948 2015 29.80409 2020 27.86451 2025 23.86843 2030 20.06128 2035 18.76656 2040 20.42835 2045 22.84526 2050 25.12944 2055 25.00815 2060 23.31528 2065 22.04665 2070 21.81027 2075 22.01185 2080 22.51643 2085 22.49074 2090 21.79085 2095 20.99325 2100 20.64271