Year Percent 1950 28.06239 1955 29.85371 1960 32.26905 1965 34.44036 1970 35.84569 1975 34.73317 1980 32.68552 1985 30.77511 1990 28.39871 1995 28.68782 2000 28.81225 2005 28.25869 2010 26.67881 2015 23.70313 2020 22.04319 2025 20.92755 2030 20.48422 2035 20.44824 2040 20.31264 2045 20.20728 2050 20.02698 2055 19.90238 2060 19.98364 2065 20.23966 2070 20.52173 2075 20.68697 2080 20.69077 2085 20.61223 2090 20.52831 2095 20.48342 2100 20.47377