Year Percent 1950 31.48131 1955 29.77329 1960 28.04797 1965 27.27266 1970 26.41794 1975 26.69391 1980 26.43095 1985 25.68384 1990 24.29491 1995 25.01835 2000 26.31456 2005 27.39058 2010 27.37272 2015 26.59547 2020 26.50095 2025 27.24307 2030 28.66878 2035 29.93421 2040 30.86002 2045 31.4312 2050 31.73494 2055 32.04012 2060 32.29048 2065 32.31362 2070 32.0814 2075 31.69305 2080 31.22503 2085 30.75992 2090 30.30202 2095 29.81442 2100 29.30392