Year Percent 1950 5.50474 1955 5.31971 1960 5.27256 1965 5.15783 1970 5.08647 1975 5.0188 1980 4.95762 1985 4.98321 1990 5.16139 1995 5.10184 2000 5.00464 2005 4.87391 2010 4.79388 2015 4.74368 2020 4.79446 2025 4.90707 2030 5.07938 2035 5.39907 2040 5.84744 2045 6.32745 2050 6.77508 2055 7.23377 2060 7.84459 2065 8.6802 2070 9.6915 2075 10.84342 2080 12.02376 2085 13.26566 2090 14.57523 2095 15.94022 2100 17.3448