Year Percent 1950 22.03346 1955 24.38471 1960 26.5493 1965 27.33043 1970 28.07955 1975 26.83143 1980 23.30877 1985 25.03563 1990 27.36234 1995 32.86326 2000 33.02554 2005 33.84758 2010 32.95075 2015 31.80459 2020 31.4177 2025 30.81656 2030 30.79363 2035 31.22937 2040 31.24406 2045 30.98889 2050 30.32861 2055 29.3914 2060 28.72118 2065 28.19991 2070 27.64362 2075 26.91465 2080 26.0456 2085 25.17055 2090 24.4315 2095 23.87088 2100 23.41154