Year Percent 1950 5.92379 1955 5.52339 1960 5.23395 1965 5.14815 1970 5.28711 1975 5.43417 1980 5.45109 1985 5.29613 1990 5.468 1995 5.31884 2000 5.191 2005 5.05281 2010 4.88001 2015 5.09334 2020 5.51675 2025 6.00951 2030 6.52447 2035 7.0841 2040 7.77348 2045 8.69941 2050 9.72172 2055 10.67483 2060 11.59276 2065 12.56716 2070 13.67991 2075 14.93794 2080 16.17766 2085 17.37865 2090 18.5405 2095 19.69787 2100 20.87356