Year Percent 1950 10.31456 1955 9.71026 1960 7.7418 1965 8.56794 1970 7.70964 1975 8.33337 1980 7.78147 1985 7.87146 1990 7.64352 1995 7.51753 2000 6.80133 2005 5.64059 2010 5.17838 2015 4.98238 2020 4.9716 2025 5.32424 2030 4.72207 2035 4.1996 2040 3.92176 2045 3.95526 2050 4.12816 2055 4.33551 2060 4.42772 2065 4.35958 2070 4.25785 2075 4.25286 2080 4.36465 2085 4.51894 2090 4.62658 2095 4.64439 2100 4.59207