Year Percent 1950 21.58007 1955 22.0748 1960 19.99556 1965 19.4996 1970 21.30581 1975 23.12494 1980 26.39285 1985 24.6278 1990 22.93789 1995 23.40267 2000 25.18076 2005 28.74795 2010 29.37276 2015 28.96727 2020 27.74864 2025 27.78252 2030 29.28431 2035 29.21935 2040 27.3576 2045 24.56075 2050 22.37377 2055 22.55088 2060 24.09803 2065 25.36179 2070 25.23076 2075 24.01639 2080 23.15532 2085 23.04815 2090 23.57399 2095 24.10663 2100 24.09307