Year Percent 1950 26.29885 1955 26.45315 1960 26.68995 1965 25.59035 1970 24.27099 1975 23.14277 1980 24.05212 1985 24.23571 1990 25.52339 1995 26.73942 2000 28.06662 2005 29.28856 2010 30.43957 2015 30.51227 2020 29.90946 2025 28.49528 2030 27.24397 2035 26.88913 2040 26.46241 2045 25.60879 2050 25.07321 2055 24.65809 2060 24.33054 2065 24.38694 2070 24.23643 2075 24.11979 2080 23.99679 2085 23.81952 2090 23.60101 2095 23.37708 2100 23.18412