Year Percent 1950 7.57541 1955 7.94519 1960 8.78061 1965 10.06677 1970 11.08308 1975 11.72349 1980 10.45206 1985 11.14508 1990 13.78669 1995 15.35397 2000 16.65017 2005 16.82254 2010 18.26927 2015 20.49748 2020 22.27526 2025 22.49498 2030 24.95565 2035 27.21977 2040 29.49368 2045 30.36621 2050 32.25106 2055 32.62775 2060 32.76081 2065 32.87696 2070 33.32951 2075 33.55367 2080 33.7943 2085 34.0411 2090 34.26514 2095 34.53043 2100 34.85948