Year Percent 1950 15.04631 1955 15.43962 1960 17.88766 1965 15.87575 1970 13.65192 1975 12.36918 1980 10.16832 1985 9.12999 1990 6.8131 1995 7.23464 2000 6.40222 2005 4.9363 2010 4.47424 2015 4.26907 2020 4.25912 2025 4.24379 2030 4.245 2035 4.03586 2040 3.68275 2045 3.52557 2050 3.58935 2055 3.75775 2060 3.93729 2065 4.04365 2070 4.01921 2075 3.92302 2080 3.90359 2085 4.00139 2090 4.14762 2095 4.26783 2100 4.28907