Year Percent 1950 16.94795 1955 18.56449 1960 18.98134 1965 18.7423 1970 17.99875 1975 17.48173 1980 16.98624 1985 15.76298 1990 14.75693 1995 14.51302 2000 13.54214 2005 11.53864 2010 10.57944 2015 9.9903 2020 9.66847 2025 9.05643 2030 8.30481 2035 7.57697 2040 6.97068 2045 6.54015 2050 6.22495 2055 5.92372 2060 5.60791 2065 5.29874 2070 5.05198 2075 4.87657 2080 4.76674 2085 4.68914 2090 4.62353 2095 4.55321 2100 4.49348