Year Percent 1950 29.15359 1955 28.32805 1960 27.50825 1965 26.58827 1970 25.49234 1975 25.60829 1980 27.59389 1985 28.09346 1990 27.82832 1995 24.65459 2000 23.28182 2005 25.81942 2010 27.87319 2015 29.0622 2020 28.99318 2025 28.47019 2030 28.5773 2035 29.29049 2040 30.4442 2045 31.21594 2050 31.19358 2055 30.92806 2060 30.77752 2065 30.85187 2070 30.97558 2075 30.88896 2080 30.53407 2085 30.08782 2090 29.7235 2095 29.46389 2100 29.21483