Year Percent 1950 3.74503 1955 3.77891 1960 3.83473 1965 4.00107 1970 4.06411 1975 4.71725 1980 5.20051 1985 5.91287 1990 6.99297 1995 7.74543 2000 8.13156 2005 9.06643 2010 11.13639 2015 14.31691 2020 17.31843 2025 20.51474 2030 23.55395 2035 25.37978 2040 26.3793 2045 26.45559 2050 26.37239 2055 26.824 2060 28.07103 2065 29.86004 2070 31.46694 2075 33.11645 2080 34.44842 2085 35.58555 2090 36.58021 2095 37.41541 2100 38.0638