Year Percent 1950 6.09582 1955 6.31764 1960 6.47779 1965 7.01683 1970 7.63138 1975 6.9438 1980 5.86529 1985 5.23736 1990 5.21287 1995 5.87451 2000 5.69911 2005 5.28277 2010 5.0407 2015 4.93289 2020 4.75957 2025 4.63234 2030 4.57275 2035 4.53993 2040 4.51487 2045 4.49179 2050 4.48144 2055 4.49652 2060 4.52163 2065 4.55395 2070 4.57592 2075 4.57711 2080 4.56748 2085 4.55412 2090 4.53794 2095 4.52578 2100 4.50738