Year Percent 1950 16.40109 1955 16.62961 1960 17.14199 1965 15.0419 1970 15.74947 1975 14.76581 1980 16.47356 1985 18.98841 1990 23.89549 1995 25.87716 2000 27.78371 2005 28.62616 2010 28.55326 2015 27.43172 2020 24.98331 2025 22.49352 2030 20.00137 2035 19.76683 2040 20.27059 2045 21.41148 2050 23.65822 2055 24.23619 2060 24.38973 2065 24.20488 2070 23.31934 2075 22.63144 2080 22.26974 2085 22.00908 2090 21.57359 2095 21.00488 2100 20.501