Year Percent 1950 15.26533 1955 16.85451 1960 17.21486 1965 15.89201 1970 16.01373 1975 15.90389 1980 16.78991 1985 17.83663 1990 19.59346 1995 23.56556 2000 28.03066 2005 30.19183 2010 31.88626 2015 32.36954 2020 31.27482 2025 29.525 2030 28.08808 2035 27.21408 2040 26.77047 2045 26.41289 2050 26.0404 2055 25.15429 2060 24.35885 2065 23.926 2070 23.81677 2075 23.66542 2080 23.45978 2085 23.20295 2090 22.86696 2095 22.57823 2100 22.37741