Year Percent 1950 29.6797 1955 29.03107 1960 28.93563 1965 29.61494 1970 31.09043 1975 30.9234 1980 30.9841 1985 31.85931 1990 32.24872 1995 32.04692 2000 29.87733 2005 28.31514 2010 27.03852 2015 27.37701 2020 26.53613 2025 24.7918 2030 23.39718 2035 22.65867 2040 22.68602 2045 23.00039 2050 23.18431 2055 22.99699 2060 22.55349 2065 22.19261 2070 22.06001 2075 22.13138 2080 22.23326 2085 22.17661 2090 21.90871 2095 21.53726 2100 21.20523