Year Percent 1950 15.68049 1955 15.3345 1960 14.41067 1965 14.64182 1970 14.51906 1975 15.23398 1980 16.65724 1985 17.50146 1990 19.26057 1995 20.93358 2000 24.19639 2005 27.7857 2010 31.03665 2015 32.90372 2020 31.90594 2025 30.70114 2030 28.40677 2035 27.19626 2040 26.43694 2045 24.66191 2050 23.54619 2055 21.67659 2060 20.56361 2065 20.76138 2070 21.49336 2075 22.11262 2080 22.14372 2085 21.76922 2090 21.19944 2095 20.88041 2100 21.06244