Year Percent 1950 4.30021 1955 4.114 1960 4.15184 1965 4.24684 1970 4.30986 1975 4.32438 1980 4.2895 1985 4.27604 1990 4.59545 1995 4.5597 2000 4.44784 2005 4.37207 2010 4.29259 2015 4.21874 2020 4.20493 2025 4.30925 2030 4.57849 2035 5.11106 2040 5.80842 2045 6.53743 2050 7.27925 2055 8.06826 2060 8.98731 2065 9.99919 2070 10.98222 2075 11.96874 2080 13.01093 2085 14.09913 2090 15.20762 2095 16.31273 2100 17.41041