Year Percent 1950 13.52431 1955 13.89129 1960 14.2466 1965 14.85828 1970 15.5432 1975 15.87495 1980 15.68631 1985 15.31033 1990 16.93129 1995 17.04638 2000 17.5456 2005 18.82534 2010 20.28756 2015 21.91484 2020 24.11538 2025 27.07858 2030 29.64724 2035 31.00985 2040 32.16513 2045 33.17773 2050 33.91348 2055 34.39019 2060 34.71719 2065 34.70057 2070 34.95715 2075 35.21382 2080 35.47505 2085 35.79525 2090 36.19386 2095 36.63813 2100 37.10386