Year Percent 1950 16.45019 1955 15.18161 1960 12.23587 1965 11.18612 1970 14.19901 1975 16.53599 1980 20.2994 1985 19.24566 1990 17.63016 1995 18.81899 2000 20.38289 2005 24.48932 2010 25.15483 2015 24.2173 2020 22.84198 2025 23.63991 2030 27.11796 2035 29.48164 2040 29.56891 2045 28.02045 2050 26.46113 2055 26.48551 2060 27.31028 2065 27.59957 2070 26.09955 2075 23.91933 2080 22.6511 2085 22.48365 2090 22.89188 2095 23.18214 2100 22.90983