Year Percent 1950 4.68025 1955 4.38819 1960 4.06844 1965 3.83493 1970 3.95014 1975 4.01922 1980 4.25545 1985 4.41897 1990 4.7452 1995 5.31325 2000 6.10056 2005 6.29414 2010 6.01052 2015 5.96913 2020 7.10141 2025 8.85796 2030 11.03102 2035 13.53523 2040 16.50319 2045 21.77639 2050 28.38724 2055 33.33265 2060 35.60062 2065 36.38304 2070 37.08755 2075 38.35646 2080 39.35257 2085 39.67663 2090 39.4532 2095 39.22506 2100 39.41667