Year Percent 1950 17.11365 1955 17.75453 1960 17.28234 1965 15.94776 1970 14.80622 1975 13.91674 1980 13.09919 1985 12.92578 1990 13.73221 1995 14.80598 2000 16.86778 2005 18.86926 2010 20.78972 2015 21.97676 2020 22.29365 2025 22.60736 2030 23.86141 2035 25.5449 2040 27.64637 2045 27.9794 2050 26.75108 2055 24.86954 2060 24.03913 2065 24.19753 2070 24.47769 2075 24.74923 2080 23.37869 2085 22.23424 2090 21.65339 2095 21.61744 2100 21.7993