Year Percent 1950 11.70552 1955 12.32764 1960 12.61536 1965 13.16831 1970 13.80298 1975 14.32867 1980 15.02973 1985 15.40934 1990 19.13987 1995 18.60458 2000 18.1813 2005 18.5049 2010 20.09993 2015 22.22661 2020 24.50495 2025 26.32189 2030 27.33396 2035 27.87214 2040 28.14846 2045 28.48833 2050 29.00298 2055 29.72439 2060 30.27909 2065 30.85981 2070 31.50857 2075 31.88098 2080 32.33834 2085 32.85377 2090 33.35296 2095 33.81815 2100 34.26212