Year Percent 1950 11.6847 1955 12.66216 1960 13.73683 1965 14.61367 1970 15.83151 1975 16.96078 1980 16.46352 1985 17.78361 1990 23.09618 1995 24.89718 2000 26.79839 2005 27.63942 2010 29.31712 2015 31.048 2020 33.03732 2025 35.86072 2030 38.77012 2035 41.2695 2040 42.51013 2045 42.70366 2050 42.40163 2055 41.88459 2060 41.22414 2065 40.73723 2070 40.54914 2075 40.28757 2080 40.17044 2085 40.19831 2090 40.36911 2095 40.65418 2100 40.99474