Year Percent 1950 4.11832 1955 3.97367 1960 3.89169 1965 3.89541 1970 3.99857 1975 4.2191 1980 4.5467 1985 4.98222 1990 6.07285 1995 6.8205 2000 7.51305 2005 7.9944 2010 8.67519 2015 9.71467 2020 11.10269 2025 12.67037 2030 14.26425 2035 15.87001 2040 17.4987 2045 19.32203 2050 21.20556 2055 23.15465 2060 24.92495 2065 26.82213 2070 28.73021 2075 30.57443 2080 32.23562 2085 33.69683 2090 34.96449 2095 36.04346 2100 36.9355