Year Percent 1950 27.91715 1955 26.36762 1960 25.9505 1965 24.8805 1970 25.71014 1975 27.92778 1980 28.76077 1985 30.80644 1990 32.03194 1995 31.91639 2000 31.98111 2005 33.21376 2010 34.34531 2015 36.48042 2020 36.72414 2025 34.58675 2030 31.30919 2035 28.65873 2040 27.36319 2045 27.07376 2050 26.97 2055 26.30433 2060 25.18538 2065 23.99432 2070 23.20026 2075 22.93289 2080 22.95515 2085 22.92118 2090 22.63111 2095 22.15871 2100 21.7324