Year Percent 1950 12.30029 1955 11.4712 1960 11.67754 1965 13.78382 1970 14.90875 1975 15.57034 1980 15.67098 1985 13.36344 1990 13.8071 1995 13.88653 2000 15.15414 2005 16.38126 2010 17.61972 2015 17.62168 2020 17.62102 2025 17.79088 2030 18.61691 2035 19.81243 2040 20.96676 2045 20.47576 2050 20.85409 2055 21.60813 2060 22.2414 2065 23.55026 2070 23.58542 2075 23.33635 2080 23.21488 2085 23.51165 2090 24.13685 2095 24.78722 2100 25.08504