Year Percent 1950 27.53743 1955 27.07668 1960 26.2219 1965 26.92347 1970 28.65928 1975 30.31763 1980 31.26329 1985 32.76376 1990 32.32425 1995 31.85631 2000 30.54964 2005 31.45528 2010 31.78642 2015 31.22851 2020 29.97884 2025 28.64779 2030 28.71891 2035 28.69024 2040 28.78232 2045 28.49915 2050 27.47547 2055 26.53847 2060 25.91692 2065 25.46283 2070 24.97567 2075 24.37144 2080 23.7295 2085 23.12623 2090 22.6312 2095 22.26121 2100 21.97846