Year	Percent
1950	9.35226
1955	9.13344
1960	9.13269
1965	8.21162
1970	10.91042
1975	9.37635
1980	10.03662
1985	11.49573
1990	11.50119
1995	11.4126
2000	10.91788
2005	10.65876
2010	10.42986
2015	10.38231
2020	9.97887
2025	10.08739
2030	10.24582
2035	9.973
2040	9.67464
2045	9.43745
2050	9.25224
2055	9.09008
2060	8.91096
2065	8.69387
2070	8.46366
2075	8.22438
2080	8.02743
2085	7.8164
2090	7.61061
2095	7.39277
2100	7.17786
