Year	Percent
1961	0.72655
1962	0.71421
1963	0.76313
1964	0.78077
1965	0.72265
1966	0.69263
1967	0.79695
1968	0.80487
1969	0.87266
1970	0.93498
1971	0.89874
1972	0.95306
1973	1.04246
1974	1.2139
1975	1.03021
1976	1.09209
1977	1.08842
1978	0.99988
1979	1.10766
1980	1.44526
1981	1.41619
1982	1.09068
1983	1.02873
1984	0.91225
1985	0.7331
1986	1.47439
1987	0.69464
1988	0.8541
1989	1.5429
1990	1.90678
1991	2.97178
1992	3.92098
1993	3.0355
1994	2.90569
1995	2.87377
1996	1.97435
1997	1.11623
2000	3.66596
2001	2.74296
2002	2.16496
2003	2.05428
2004	1.58515
2005	1.42698
2006	1.48651
2007	1.34709
2008	0.94377
2009	1.07607
2010	0.97215
2011	0.86579
2012	0.78275
2013	0.64396
2014	0.97326
2015	0.93069
2016	0.82072
2017	0.72333