Year	Percent
1950	15.36976
1955	15.86089
1960	16.77419
1965	17.5465
1970	18.14441
1975	18.51015
1980	18.81922
1985	19.38186
1990	19.42834
1995	19.34296
2000	19.84712
2005	18.98573
2010	17.98565
2015	15.46154
2020	14.27618
2025	13.04394
2030	12.00808
2035	11.05572
2040	10.15258
2045	9.29364
2050	8.51881
2055	7.87436
2060	7.34496
2065	6.89648
2070	6.52572
2075	6.20812
2080	5.94429
2085	5.73891
2090	5.58445
2095	5.45711
2100	5.35114