Year Percent 1950 29.62218 1955 28.11959 1960 26.93791 1965 25.92711 1970 27.39754 1975 28.84405 1980 30.69103 1985 32.37068 1990 32.04101 1995 31.02395 2000 28.99147 2005 26.64997 2010 24.69495 2015 24.04578 2020 23.93725 2025 23.8574 2030 23.09174 2035 22.17019 2040 21.69668 2045 21.37586 2050 21.50217 2055 21.77664 2060 21.8021 2065 21.56405 2070 21.24634 2075 21.02988 2080 20.97233 2085 21.01236 2090 20.99885 2095 20.84547 2100 20.61704