Year Percent 1950 12.75683 1955 13.03115 1960 13.53501 1965 13.78244 1970 14.53082 1975 15.31751 1980 15.61788 1985 15.91656 1990 19.4537 1995 19.49756 2000 20.15254 2005 21.27523 2010 22.82636 2015 23.50318 2020 25.31934 2025 28.02013 2030 30.63389 2035 32.04594 2040 32.95374 2045 34.18116 2050 35.02202 2055 35.44992 2060 35.40932 2065 35.2322 2070 35.243 2075 35.551 2080 36.07325 2085 36.58397 2090 37.06547 2095 37.52366 2100 38.01398