Year Percent 1950 20.27625 1955 20.91627 1960 18.34097 1965 18.58765 1970 21.29078 1975 22.03671 1980 26.40636 1985 25.81405 1990 24.53983 1995 26.31392 2000 26.23016 2005 28.4536 2010 28.14958 2015 27.95144 2020 28.3316 2025 29.82497 2030 32.28119 2035 32.22278 2040 30.01052 2045 26.51913 2050 24.38197 2055 24.5132 2060 25.92017 2065 27.21057 2070 26.64808 2075 25.48564 2080 24.6387 2085 24.49028 2090 24.88476 2095 25.29933 2100 25.24473