Year Percent 1950 13.09108 1955 12.20157 1960 11.72288 1965 12.49439 1970 12.66095 1975 13.91955 1980 14.17451 1985 15.09064 1990 14.92709 1995 15.07336 2000 15.00464 2005 15.40122 2010 15.55157 2015 15.37123 2020 15.10941 2025 14.52042 2030 13.87511 2035 13.23045 2040 12.59521 2045 11.94417 2050 11.25892 2055 10.5866 2060 9.97403 2065 9.44723 2070 8.98313 2075 8.57637 2080 8.19608 2085 7.8466 2090 7.53679 2095 7.28317 2100 7.04931