Year Percent 1950 13.38983 1955 12.69931 1960 11.75473 1965 12.09391 1970 13.96157 1975 13.09049 1980 11.93705 1985 11.23263 1990 9.49236 1995 8.69955 2000 6.95687 2005 7.58797 2010 6.68932 2015 5.19824 2020 4.59306 2025 4.43585 2030 4.47545 2035 4.52754 2040 4.62611 2045 4.50217 2050 4.19336 2055 4.07743 2060 4.19115 2065 4.4052 2070 4.61704 2075 4.73781 2080 4.69804 2085 4.56572 2090 4.51299 2095 4.58484 2100 4.70681