Year Percent 1950 16.70522 1955 16.91908 1960 17.13119 1965 17.55087 1970 17.86432 1975 17.79649 1980 15.8801 1985 16.63394 1990 21.84355 1995 22.7607 2000 23.07105 2005 23.11502 2010 25.25875 2015 27.20267 2020 28.90508 2025 30.63057 2030 32.17994 2035 33.47421 2040 33.90473 2045 34.27586 2050 34.38479 2055 34.30964 2060 34.42111 2065 34.74874 2070 35.22716 2075 35.67628 2080 36.10461 2085 36.52826 2090 37.0009 2095 37.5342 2100 38.04712