Year	Percent
1950	30.09946
1955	29.29451
1960	30.10803
1965	28.13595
1970	27.40514
1975	26.74454
1980	26.6733
1985	28.26756
1990	28.99276
1995	29.54478
2000	28.66127
2005	26.64343
2010	23.95292
2015	21.34099
2020	19.92138
2025	19.5914
2030	19.77647
2035	19.70325
2040	19.5155
2045	19.14614
2050	18.78268
2055	18.91944
2060	19.33482
2065	19.81025
2070	20.10306
2075	20.12775
2080	19.96893
2085	19.79916
2090	19.72809
2095	19.74252
2100	19.75334