Year Percent 1950 4.11679 1955 4.08795 1960 4.1049 1965 4.14708 1970 4.18479 1975 4.20055 1980 4.18345 1985 4.18761 1990 4.45447 1995 4.33936 2000 4.30225 2005 4.25406 2010 4.22045 2015 4.25347 2020 4.26173 2025 4.23039 2030 4.1911 2035 4.3658 2040 4.73102 2045 5.25323 2050 5.86536 2055 6.62712 2060 7.54714 2065 8.61884 2070 9.76863 2075 10.94958 2080 12.11788 2085 13.34222 2090 14.63509 2095 15.9673 2100 17.30641