Year Percent 1950 11.44134 1955 9.36403 1960 7.8317 1965 7.80286 1970 8.23014 1975 8.56122 1980 8.03604 1985 8.2621 1990 11.52255 1995 13.87532 2000 16.63275 2005 15.85143 2010 16.28196 2015 17.66278 2020 21.03876 2025 24.18968 2030 25.82144 2035 27.03421 2040 28.90975 2045 32.13443 2050 36.11773 2055 38.86124 2060 39.05305 2065 38.85456 2070 39.57433 2075 40.58919 2080 40.99648 2085 40.81655 2090 40.36588 2095 40.06858 2100 40.18747