Year Percent 1950 30.67742 1955 29.67239 1960 28.47196 1965 27.1421 1970 25.82665 1975 25.82424 1980 26.29772 1985 26.75926 1990 27.26202 1995 27.4735 2000 27.90514 2005 28.94855 2010 30.0506 2015 30.68232 2020 30.96753 2025 30.95372 2030 31.07026 2035 31.51409 2040 31.84843 2045 31.9343 2050 31.71605 2055 31.30554 2060 30.98874 2065 30.77673 2070 30.58873 2075 30.33904 2080 30.02336 2085 29.67104 2090 29.34151 2095 29.03196 2100 28.70385