Year Percent 1950 16.73343 1955 17.00824 1960 17.34922 1965 17.87206 1970 18.33438 1975 18.72818 1980 18.81076 1985 18.45912 1990 17.82515 1995 16.87551 2000 16.31007 2005 16.61688 2010 16.45524 2015 15.57467 2020 14.65697 2025 13.94024 2030 13.41439 2035 12.89631 2040 12.33245 2045 11.74597 2050 11.16956 2055 10.66992 2060 10.19679 2065 9.77479 2070 9.34687 2075 8.92533 2080 8.53439 2085 8.17424 2090 7.81864 2095 7.50582 2100 7.21481