Year Percent 1950 22.01825 1955 23.00001 1960 20.81785 1965 21.33185 1970 21.25678 1975 20.78371 1980 21.15944 1985 20.12282 1990 20.80993 1995 23.23693 2000 26.15159 2005 28.03348 2010 28.3769 2015 28.40571 2020 29.58082 2025 30.78514 2030 32.06946 2035 31.73601 2040 29.11537 2045 26.36475 2050 24.54168 2055 23.63107 2060 24.11969 2065 24.96155 2070 24.96711 2075 24.44863 2080 23.79678 2085 23.40457 2090 23.45177 2095 23.76955 2100 23.95044