Year Percent 1950 9.52993 1955 10.94985 1960 11.24659 1965 11.29154 1970 10.45008 1975 8.19845 1980 7.16561 1985 6.79934 1990 6.70704 1995 6.56606 2000 6.41013 2005 5.58871 2010 5.08821 2015 5.25048 2020 5.1846 2025 5.09088 2030 4.96367 2035 4.82998 2040 4.70858 2045 4.71048 2050 4.79354 2055 4.86214 2060 4.87775 2065 4.84622 2070 4.80508 2075 4.78411 2080 4.79304 2085 4.80643 2090 4.80602 2095 4.77814 2100 4.73373