Year Percent 1950 4.48751 1955 4.29558 1960 4.22414 1965 4.19577 1970 4.21735 1975 4.21035 1980 4.16781 1985 4.0842 1990 4.1654 1995 4.00598 2000 3.86157 2005 3.7142 2010 3.60267 2015 3.91417 2020 4.14877 2025 4.37044 2030 4.58445 2035 4.87376 2040 5.2508 2045 5.64218 2050 6.09949 2055 6.59447 2060 7.16614 2065 7.91769 2070 8.84666 2075 9.80896 2080 10.77506 2085 11.77148 2090 12.81584 2095 13.90102 2100 15.0131