Year Percent 1950 9.99756 1955 10.15143 1960 11.46523 1965 12.94893 1970 14.1048 1975 15.15123 1980 13.08264 1985 13.88055 1990 15.92043 1995 16.2052 2000 16.3979 2005 17.32376 2010 17.9619 2015 20.7625 2020 22.40831 2025 22.86753 2030 24.05855 2035 26.4332 2040 29.17523 2045 30.26743 2050 31.29068 2055 32.73862 2060 33.0044 2065 33.08556 2070 33.35544 2075 33.45569 2080 33.67948 2085 33.96987 2090 34.29851 2095 34.56993 2100 34.8276