Year Percent 1950 4.80811 1955 4.9743 1960 5.18191 1965 5.34139 1970 5.36187 1975 5.10823 1980 5.05546 1985 5.5788 1990 7.03517 1995 7.81377 2000 8.45185 2005 8.85254 2010 9.11032 2015 10.34616 2020 12.23258 2025 14.30507 2030 16.40522 2035 18.57798 2040 20.88212 2045 23.48589 2050 25.72004 2055 27.69604 2060 29.00876 2065 30.18677 2070 31.41778 2075 33.09287 2080 34.52803 2085 35.70699 2090 36.66981 2095 37.50371 2100 38.29974