Year Percent 1950 6.75673 1955 6.55144 1960 6.36865 1965 6.97236 1970 7.50409 1975 7.58116 1980 7.12123 1985 5.83754 1990 5.51663 1995 5.62687 2000 5.91787 2005 6.27116 2010 6.07062 2015 5.52422 2020 5.29155 2025 5.39721 2030 5.59994 2035 5.55365 2040 5.46973 2045 5.40383 2050 5.33574 2055 5.31202 2060 5.358 2065 5.4092 2070 5.4029 2075 5.3568 2080 5.29269 2085 5.23121 2090 5.1865 2095 5.15976 2100 5.12492