Year Percent 1950 12.64205 1955 12.40285 1960 13.93282 1965 14.17205 1970 15.02803 1975 16.41294 1980 16.78582 1985 15.96643 1990 14.42985 1995 13.32056 2000 11.36684 2005 9.86273 2010 9.19003 2015 9.42455 2020 9.25161 2025 8.20494 2030 7.30311 2035 6.56924 2040 6.12693 2045 5.94852 2050 5.86837 2055 5.7163 2060 5.47083 2065 5.22088 2070 5.06781 2075 5.02333 2080 5.03865 2085 5.04103 2090 4.99165 2095 4.90331 2100 4.83598