Year	Percent
1950	20.17528
1955	21.08776
1960	19.45401
1965	18.78137
1970	18.74274
1975	18.18635
1980	16.0724
1985	16.09735
1990	17.13488
1995	20.48971
2000	24.24182
2005	27.52757
2010	28.50757
2015	28.59864
2020	27.13673
2025	25.76078
2030	24.77469
2035	23.87105
2040	23.45344
2045	22.98525
2050	22.90841
2055	22.82066
2060	22.88596
2065	22.8167
2070	22.72214
2075	22.56526
2080	22.43914
2085	22.35327
2090	22.28137
2095	22.21285
2100	22.11853