Year Percent 1950 3.45552 1955 3.59158 1960 3.69443 1965 3.74085 1970 3.76793 1975 3.79869 1980 3.87302 1985 4.02376 1990 4.50675 1995 4.736 2000 4.85878 2005 4.92603 2010 5.03264 2015 5.10491 2020 5.17095 2025 5.19096 2030 5.20355 2035 5.2844 2040 5.48637 2045 5.73491 2050 6.10442 2055 6.6337 2060 7.27481 2065 7.86907 2070 8.43448 2075 9.08504 2080 9.8068 2085 10.54604 2090 11.28275 2095 12.02879 2100 12.78722