Year Percent 1950 12.63289 1955 13.0538 1960 16.29731 1965 17.79567 1970 18.65381 1975 17.45346 1980 17.39661 1985 19.33957 1990 18.94617 1995 16.04754 2000 11.92474 2005 9.11796 2010 8.493 2015 8.42161 2020 7.43483 2025 6.14885 2030 5.06491 2035 4.53514 2040 4.51829 2045 4.63834 2050 4.53637 2055 4.19731 2060 3.84961 2065 3.68619 2070 3.75039 2075 3.91816 2080 4.03871 2085 4.03974 2090 3.96993 2095 3.92667 2100 3.96319