Year Percent 1950 27.28827 1955 28.31051 1960 28.75915 1965 28.57093 1970 28.51953 1975 26.98108 1980 26.33357 1985 27.73811 1990 27.93878 1995 28.88602 2000 30.55977 2005 30.74635 2010 32.88836 2015 34.39834 2020 34.83492 2025 34.94105 2030 33.37165 2035 32.18054 2040 31.15826 2045 30.35428 2050 29.86613 2055 29.20815 2060 28.41518 2065 27.57354 2070 26.82425 2075 26.27059 2080 25.89915 2085 25.60409 2090 25.30083 2095 24.96283 2100 24.63782