Year Percent 1950 17.73051 1955 19.34896 1960 19.12994 1965 18.69836 1970 18.56957 1975 18.90859 1980 16.60074 1985 14.78816 1990 13.83695 1995 12.89684 2000 12.04782 2005 11.14904 2010 10.01774 2015 9.40096 2020 8.62956 2025 7.89179 2030 7.22029 2035 6.67342 2040 6.23834 2045 5.90043 2050 5.61158 2055 5.3635 2060 5.13387 2065 4.96146 2070 4.82707 2075 4.73449 2080 4.66744 2085 4.61255 2090 4.57235 2095 4.54065 2100 4.52113