Year Percent 1950 8.51183 1955 9.18596 1960 9.55172 1965 9.95823 1970 10.16303 1975 10.16118 1980 10.5464 1985 10.89829 1990 13.39872 1995 13.8303 2000 13.82509 2005 14.64308 2010 15.85989 2015 18.30522 2020 20.77337 2025 22.89616 2030 24.48671 2035 25.93455 2040 27.12794 2045 28.53659 2050 29.64576 2055 31.33193 2060 32.15869 2065 32.81985 2070 33.9934 2075 34.86273 2080 35.60827 2085 36.24702 2090 36.78107 2095 37.26538 2100 37.76507