Year	Percent
1950	17.22014
1955	17.34604
1960	17.6099
1965	18.09106
1970	18.43557
1975	18.94383
1980	19.34685
1985	19.38829
1990	18.63182
1995	16.27094
2000	14.10197
2005	12.77224
2010	11.9631
2015	10.67729
2020	10.20703
2025	9.05847
2030	7.77679
2035	6.92627
2040	6.47054
2045	6.30175
2050	6.1854
2055	5.94
2060	5.59298
2065	5.27165
2070	5.08933
2075	5.04899
2080	5.06231
2085	5.03422
2090	4.93845
2095	4.81273
2100	4.718