Year Percent 1950 26.79575 1955 26.75444 1960 26.75362 1965 26.76845 1970 27.8943 1975 28.24023 1980 28.67402 1985 29.29713 1990 29.79333 1995 29.90565 2000 29.81818 2005 30.41452 2010 31.45436 2015 31.58673 2020 31.73033 2025 31.03345 2030 30.53236 2035 30.34157 2040 30.04648 2045 29.88838 2050 29.15512 2055 28.68042 2060 28.20971 2065 27.78684 2070 27.36802 2075 26.90509 2080 26.4175 2085 25.90399 2090 25.38852 2095 24.88268 2100 24.38315