Year Percent 1950 5.19911 1955 4.84103 1960 4.47002 1965 3.15011 1970 3.14064 1975 2.87423 1980 2.41811 1985 2.15764 1990 2.1056 1995 2.41323 2000 3.02404 2005 3.62324 2010 3.37866 2015 3.54178 2020 5.25819 2025 7.6814 2030 11.55683 2035 15.62221 2040 18.52549 2045 21.07384 2050 22.47013 2055 22.90675 2060 23.8832 2065 24.30827 2070 25.07918 2075 26.2382 2080 27.47248 2085 28.26274 2090 28.82523 2095 29.37176 2100 29.96754