Year Percent 1950 4.05621 1955 3.70988 1960 3.53743 1965 3.45035 1970 3.44533 1975 3.51724 1980 3.61776 1985 3.838 1990 4.38008 1995 4.71263 2000 5.11503 2005 5.61831 2010 5.92617 2015 6.97215 2020 8.34985 2025 9.60123 2030 10.93602 2035 12.71393 2040 15.00684 2045 17.8871 2050 20.98042 2055 23.99458 2060 26.80404 2065 29.27782 2070 31.6153 2075 33.58969 2080 35.18881 2085 36.39867 2090 37.31429 2095 38.00047 2100 38.53093