Year Percent 1950 31.03687 1955 29.35138 1960 24.2957 1965 25.99003 1970 27.10662 1975 30.51292 1980 33.59522 1985 34.54902 1990 35.61533 1995 35.23411 2000 34.64658 2005 33.61344 2010 30.18561 2015 29.15945 2020 30.0314 2025 29.67101 2030 28.91072 2035 27.76399 2040 26.64626 2045 25.95269 2050 25.57278 2055 25.18015 2060 24.63413 2065 23.98268 2070 23.39023 2075 22.95928 2080 22.6526 2085 22.39141 2090 22.11908 2095 21.84163 2100 21.63613