Year Percent 1950 14.06607 1955 14.18839 1960 13.16806 1965 12.87151 1970 13.25271 1975 13.29288 1980 13.31948 1985 11.97125 1990 12.67929 1995 13.00883 2000 14.14991 2005 16.90254 2010 17.91798 2015 18.76281 2020 19.70304 2025 21.49012 2030 25.84893 2035 28.15019 2040 28.78577 2045 27.14562 2050 24.98243 2055 24.78672 2060 25.44261 2065 26.25432 2070 25.73574 2075 24.35135 2080 23.0882 2085 22.63707 2090 22.86963 2095 23.09949 2100 22.76324