Year	Percent
1950	16.01924
1955	15.73628
1960	17.21344
1965	18.05568
1970	18.24942
1975	17.36793
1980	17.44543
1985	16.78807
1990	15.44403
1995	13.97095
2000	12.77474
2005	11.69868
2010	10.50749
2015	9.57798
2020	8.86485
2025	8.11163
2030	7.41105
2035	6.77885
2040	6.26343
2045	5.88308
2050	5.57583
2055	5.31726
2060	5.10227
2065	4.92432
2070	4.78905
2075	4.68312
2080	4.60756
2085	4.55771
2090	4.52372
2095	4.50755
2100	4.50356