Year Percent 1950 32.17457 1955 30.92216 1960 29.79545 1965 28.64429 1970 27.48124 1975 27.87101 1980 27.81889 1985 27.73061 1990 28.05474 1995 27.57381 2000 28.80416 2005 29.43064 2010 30.52786 2015 32.42855 2020 34.0252 2025 34.69604 2030 34.08495 2035 32.0441 2040 29.70869 2045 27.55439 2050 25.80303 2055 24.68853 2060 23.33074 2065 21.97923 2070 20.88801 2075 20.20554 2080 19.8236 2085 19.54968 2090 19.32012 2095 19.134 2100 19.03128