Year Percent 1950 27.92444 1955 27.29911 1960 26.78483 1965 26.55242 1970 26.69777 1975 27.36928 1980 28.57896 1985 30.09644 1990 31.51951 1995 32.66983 2000 32.92557 2005 32.48234 2010 31.68336 2015 30.60763 2020 29.90395 2025 29.30937 2030 28.81264 2035 28.50022 2040 27.96655 2045 27.44427 2050 26.85815 2055 26.15152 2060 25.52978 2065 24.94779 2070 24.36691 2075 23.79064 2080 23.24212 2085 22.73591 2090 22.28168 2095 21.88938 2100 21.55148