Year Percent 1950 9.61174 1955 8.37144 1960 8.16902 1965 8.40586 1970 8.27448 1975 8.27312 1980 7.64749 1985 7.39144 1990 9.56448 1995 9.89088 2000 10.39579 2005 9.57846 2010 9.21789 2015 10.51632 2020 13.18797 2025 16.72237 2030 19.39267 2035 21.27122 2040 22.83549 2045 25.18273 2050 28.19106 2055 30.37636 2060 30.8161 2065 30.40011 2070 30.38437 2075 31.71935 2080 32.70329 2085 33.06519 2090 33.23782 2095 33.65629 2100 34.28277