Year Percent 1950 13.49779 1955 14.62562 1960 15.81268 1965 17.0508 1970 18.31096 1975 18.60666 1980 17.55652 1985 17.94811 1990 22.31254 1995 22.03766 2000 21.5657 2005 21.35154 2010 20.87538 2015 20.76656 2020 21.93683 2025 23.57485 2030 25.51109 2035 26.95457 2040 27.96829 2045 29.33345 2050 30.0021 2055 30.41374 2060 30.85622 2065 31.13465 2070 31.36006 2075 31.71306 2080 32.32092 2085 32.99348 2090 33.69272 2095 34.38468 2100 35.07247