Year	Percent
1950	18.50738
1955	19.22172
1960	19.18974
1965	19.31603
1970	19.57222
1975	19.53756
1980	19.63168
1985	19.77227
1990	20.01199
1995	20.49856
2000	20.51883
2005	20.45396
2010	19.87373
2015	18.99706
2020	18.10269
2025	17.27349
2030	16.42534
2035	15.52768
2040	14.62066
2045	13.76327
2050	12.96031
2055	12.21433
2060	11.50953
2065	10.83831
2070	10.21546
2075	9.63934
2080	9.10487
2085	8.61647
2090	8.16582
2095	7.75314
2100	7.36989