Year Percent 1950 26.67571 1955 27.64385 1960 24.94081 1965 25.01876 1970 23.9285 1975 22.46392 1980 22.95985 1985 22.9196 1990 24.9573 1995 27.13987 2000 28.93352 2005 28.96243 2010 27.54763 2015 28.31309 2020 30.53452 2025 31.33039 2030 31.63026 2035 29.73493 2040 25.80241 2045 23.65772 2050 22.86217 2055 22.74786 2060 24.04239 2065 24.82638 2070 24.25869 2075 23.54062 2080 23.05169 2085 23.04218 2090 23.39703 2095 23.76062 2100 23.69727