Year	Percent
1950	30.92229
1955	30.49509
1960	29.63176
1965	27.82902
1970	25.87084
1975	26.25719
1980	27.18972
1985	28.97459
1990	29.50856
1995	30.88406
2000	31.37988
2005	30.91453
2010	28.30631
2015	25.23487
2020	23.33172
2025	22.8585
2030	23.0228
2035	22.90134
2040	21.98413
2045	20.71744
2050	19.81679
2055	19.50376
2060	19.80868
2065	20.27578
2070	20.4378
2075	20.23562
2080	19.8936
2085	19.69109
2090	19.76663
2095	20.03724
2100	20.26619