Year Percent 1950 10.67666 1955 10.01033 1960 9.52455 1965 8.63708 1970 11.20318 1975 11.51948 1980 10.65368 1985 10.44926 1990 10.89964 1995 11.27528 2000 11.58054 2005 11.19877 2010 10.40199 2015 9.47255 2020 8.66486 2025 8.30306 2030 7.80615 2035 7.30753 2040 6.7553 2045 6.2769 2050 5.88161 2055 5.58173 2060 5.33404 2065 5.12194 2070 4.94632 2075 4.79491 2080 4.69101 2085 4.61695 2090 4.56274 2095 4.53009 2100 4.49966