Year Percent 1950 10.31489 1955 10.42093 1960 11.48878 1965 13.12702 1970 14.5833 1975 15.08735 1980 12.64319 1985 13.17992 1990 14.66049 1995 14.82067 2000 15.04061 2005 16.77953 2010 19.36029 2015 21.85352 2020 23.33889 2025 24.62621 2030 26.056 2035 28.89731 2040 32.12491 2045 33.7124 2050 34.88019 2055 35.27066 2060 34.13928 2065 33.20936 2070 33.23909 2075 33.29091 2080 33.49129 2085 33.70656 2090 33.80226 2095 33.86453 2100 34.15805