Year Percent 1950 10.30719 1955 7.88135 1960 7.42807 1965 6.67652 1970 6.98138 1975 7.3395 1980 6.66957 1985 6.01418 1990 7.24839 1995 7.49597 2000 8.22813 2005 8.24289 2010 7.90036 2015 7.95829 2020 8.58859 2025 10.16601 2030 11.55307 2035 12.60906 2040 14.01039 2045 16.15863 2050 19.07627 2055 22.31136 2060 25.20769 2065 27.59853 2070 29.60879 2075 31.23666 2080 32.73686 2085 34.02935 2090 35.0623 2095 35.86951 2100 36.51426