Year Percent 1950 4.65699 1955 4.2792 1960 4.01736 1965 4.3439 1970 4.68046 1975 4.79628 1980 4.82801 1985 4.45406 1990 4.17307 1995 4.1723 2000 4.05546 2005 3.98413 2010 3.71953 2015 3.75669 2020 3.9142 2025 4.15671 2030 4.51236 2035 4.76262 2040 5.27521 2045 5.83624 2050 6.39801 2055 7.07403 2060 7.95261 2065 9.02303 2070 10.24134 2075 11.59116 2080 12.96901 2085 14.34529 2090 15.7064 2095 17.04741 2100 18.33718