Year Percent 1950 4.16282 1955 4.22774 1960 4.41492 1965 4.49598 1970 4.53319 1975 4.55434 1980 4.69797 1985 5.11104 1990 6.70305 1995 7.85098 2000 9.12276 2005 10.30835 2010 11.93297 2015 14.33336 2020 17.57129 2025 21.09754 2030 24.62819 2035 27.6175 2040 29.85782 2045 31.14264 2050 31.88064 2055 33.1418 2060 34.59385 2065 35.61431 2070 36.46161 2075 37.09162 2080 37.19656 2085 37.06812 2090 36.98251 2095 36.95743 2100 36.95327