Year Percent 1950 28.14059 1955 27.24095 1960 26.50343 1965 26.1481 1970 26.11818 1975 27.53695 1980 29.69276 1985 29.47424 1990 29.42853 1995 33.57232 2000 34.84017 2005 36.71247 2010 45.81224 2015 50.57936 2020 50.78399 2025 44.8899 2030 38.9607 2035 34.9428 2040 33.93302 2045 33.29996 2050 30.63281 2055 27.40399 2060 24.75292 2065 23.42691 2070 23.1162 2075 23.10104 2080 22.93351 2085 22.46939 2090 21.90631 2095 21.52256 2100 21.43364