Year Percent 1950 5.52703 1955 5.43503 1960 5.33669 1965 6.06374 1970 7.03467 1975 7.64452 1980 7.41854 1985 6.82925 1990 8.56797 1995 9.02961 2000 9.66098 2005 9.44236 2010 9.52202 2015 10.936 2020 13.21903 2025 16.26972 2030 18.34246 2035 20.16058 2040 21.97979 2045 23.91471 2050 25.72162 2055 27.67624 2060 29.59661 2065 31.15451 2070 32.8902 2075 34.35383 2080 35.65118 2085 36.68374 2090 37.49689 2095 38.17309 2100 38.79977