Year Percent 1950 28.06658 1955 26.57049 1960 25.292 1965 24.30844 1970 24.86888 1975 27.07548 1980 29.45079 1985 31.89125 1990 33.54764 1995 33.28319 2000 33.32024 2005 33.24485 2010 32.89589 2015 33.08916 2020 32.40233 2025 31.34475 2030 30.05556 2035 28.62441 2040 27.46551 2045 26.21683 2050 25.15823 2055 24.29144 2060 23.55162 2065 22.97981 2070 22.52457 2075 22.17241 2080 21.90255 2085 21.69147 2090 21.53288 2095 21.41978 2100 21.33383