Year Percent 1950 5.18785 1955 5.10086 1960 5.01659 1965 4.88882 1970 4.75416 1975 4.50342 1980 4.18994 1985 3.92793 1990 4.08734 1995 4.00645 2000 3.7644 2005 3.48039 2010 3.48745 2015 3.72584 2020 4.04076 2025 4.45671 2030 5.05632 2035 5.96835 2040 7.16903 2045 8.54534 2050 9.89084 2055 11.00479 2060 12.33608 2065 13.79654 2070 15.37809 2075 16.80385 2080 18.20988 2085 19.61427 2090 21.03467 2095 22.44653 2100 23.81369