Year Percent 1950 25.17646 1955 26.25058 1960 23.84712 1965 24.92878 1970 24.95794 1975 24.29004 1980 25.4161 1985 24.80832 1990 25.00592 1995 26.71187 2000 28.03385 2005 27.34289 2010 28.00958 2015 27.68722 2020 28.94298 2025 29.82561 2030 29.78178 2035 29.03614 2040 26.78522 2045 25.97393 2050 25.46703 2055 24.2235 2060 24.10503 2065 24.16688 2070 24.03218 2075 24.02566 2080 23.88373 2085 23.70552 2090 23.52001 2095 23.42576 2100 23.36836