Year Percent 1950 29.30933 1955 26.61599 1960 26.60901 1965 23.94894 1970 24.63103 1975 22.3533 1980 27.53315 1985 30.23551 1990 32.71835 1995 31.51429 2000 31.32242 2005 25.49793 2010 23.48391 2015 21.29013 2020 20.25844 2025 20.70999 2030 20.75693 2035 20.93031 2040 20.47148 2045 19.38984 2050 18.30714 2055 18.98663 2060 19.37449 2065 19.76959 2070 19.79145 2075 19.44488 2080 18.98269 2085 18.76813 2090 18.85003 2095 18.93212 2100 18.89554