Year Percent 1950 22.33915 1955 23.77956 1960 25.54088 1965 26.36104 1970 27.05366 1975 26.01299 1980 25.12373 1985 25.66263 1990 25.92244 1995 26.34681 2000 27.1394 2005 27.8087 2010 28.94255 2015 30.76917 2020 31.78412 2025 31.9463 2030 31.83833 2035 31.42484 2040 31.32237 2045 31.49533 2050 31.32609 2055 30.79767 2060 30.12298 2065 29.51188 2070 29.01673 2075 28.55859 2080 28.03523 2085 27.42365 2090 26.75414 2095 26.09861 2100 25.50157