Year Percent 1950 9.27673 1955 10.86004 1960 10.70891 1965 11.1607 1970 10.71276 1975 9.85829 1980 9.39081 1985 7.83921 1990 7.46849 1995 7.78414 2000 7.81679 2005 7.06916 2010 6.5657 2015 6.83998 2020 6.49404 2025 6.30263 2030 6.12677 2035 5.91731 2040 5.70213 2045 5.56375 2050 5.49279 2055 5.42541 2060 5.35395 2065 5.26112 2070 5.16149 2075 5.07566 2080 5.0143 2085 4.96762 2090 4.92743 2095 4.87969 2100 4.82816