Year Percent 1950 13.40573 1955 13.34841 1960 15.20461 1965 16.98615 1970 19.09724 1975 17.39237 1980 15.65566 1985 14.58367 1990 12.57517 1995 11.96836 2000 11.33634 2005 9.77601 2010 7.77597 2015 6.37815 2020 6.0842 2025 5.82425 2030 5.50327 2035 5.18239 2040 4.8335 2045 4.51954 2050 4.34561 2055 4.29159 2060 4.27515 2065 4.23874 2070 4.17836 2075 4.12685 2080 4.12288 2085 4.17372 2090 4.25048 2095 4.31877 2100 4.35057