Year Percent 1950 27.26634 1955 25.808 1960 24.96058 1965 24.32954 1970 24.34186 1975 26.10889 1980 27.34856 1985 28.47092 1990 29.22612 1995 28.82349 2000 28.8934 2005 29.97499 2010 31.41855 2015 33.10829 2020 33.91908 2025 33.0696 2030 31.83584 2035 30.53117 2040 29.40769 2045 28.82711 2050 28.12338 2055 27.35568 2060 26.4111 2065 25.49882 2070 24.76611 2075 24.02164 2080 23.39359 2085 22.91627 2090 22.53356 2095 22.18705 2100 21.86172