Year Percent 1950 8.06791 1955 8.05868 1960 8.56027 1965 9.69915 1970 12.82034 1975 13.50189 1980 13.3041 1985 13.71936 1990 17.59018 1995 18.93483 2000 19.92254 2005 20.68274 2010 21.97083 2015 23.50392 2020 25.43484 2025 27.73504 2030 30.87778 2035 33.96072 2040 36.98794 2045 39.17606 2050 39.72467 2055 39.77455 2060 39.76954 2065 39.73974 2070 40.24733 2075 40.22545 2080 39.81651 2085 39.32822 2090 39.03251 2095 38.95087 2100 39.06291