Year Percent 1950 19.78411 1955 20.60544 1960 19.34457 1965 18.71486 1970 20.74844 1975 22.19164 1980 25.26923 1985 24.26183 1990 21.92346 1995 21.98929 2000 22.37005 2005 25.14731 2010 26.71804 2015 27.01001 2020 26.48848 2025 25.87364 2030 26.54048 2035 26.73635 2040 25.57422 2045 23.85276 2050 22.94826 2055 23.29572 2060 24.39792 2065 25.47665 2070 24.96479 2075 23.51059 2080 22.87546 2085 23.08158 2090 23.57464 2095 23.73626 2100 23.3767