Year Percent 1950 5.67779 1955 4.31461 1960 3.93483 1965 3.7749 1970 3.73988 1975 3.7142 1980 3.76495 1985 3.8615 1990 4.21921 1995 4.33723 2000 4.4365 2005 4.55043 2010 4.75361 2015 5.19211 2020 5.67087 2025 6.18553 2030 6.75982 2035 7.43687 2040 8.1942 2045 8.94632 2050 9.58369 2055 10.28356 2060 11.20939 2065 12.16341 2070 13.07637 2075 13.87748 2080 14.64182 2085 15.44553 2090 16.29835 2095 17.19342 2100 18.10493