Year Percent 1950 5.12474 1955 5.008 1960 5.09082 1965 5.39264 1970 5.64328 1975 5.59117 1980 5.30452 1985 5.32769 1990 5.57348 1995 5.58259 2000 5.37105 2005 5.36083 2010 5.72175 2015 5.55282 2020 5.02191 2025 4.42611 2030 4.14075 2035 4.35634 2040 5.16173 2045 6.61051 2050 8.40175 2055 10.22202 2060 11.98953 2065 13.33107 2070 14.56742 2075 16.16439 2080 17.84342 2085 19.39771 2090 20.76619 2095 22.04244 2100 23.27626