Year Percent 1950 5.40326 1955 5.5447 1960 5.54012 1965 5.35364 1970 5.09036 1975 4.75581 1980 4.37647 1985 3.71817 1990 4.30541 1995 4.30876 2000 4.42691 2005 4.44954 2010 4.48347 2015 5.23727 2020 6.37548 2025 8.44556 2030 11.03412 2035 14.39958 2040 17.87464 2045 20.44529 2050 22.91077 2055 25.10126 2060 26.24188 2065 27.06836 2070 28.22009 2075 29.58372 2080 31.24482 2085 32.60806 2090 33.5231 2095 34.12527 2100 34.60133