Year Percent 1950 9.461 1955 8.96904 1960 9.93785 1965 11.15271 1970 13.26001 1975 12.9989 1980 12.90398 1985 13.37785 1990 16.2581 1995 17.57125 2000 18.63807 2005 20.62148 2010 24.86923 2015 26.97639 2020 29.43909 2025 31.05564 2030 31.61211 2035 32.61786 2040 34.12988 2045 35.82756 2050 37.58822 2055 39.1283 2060 39.74158 2065 39.68781 2070 39.39608 2075 39.33992 2080 39.38179 2085 39.51824 2090 39.617 2095 39.60985 2100 39.62035