Year	Percent
1965	1.1775
1966	1.14519
1967	1.16858
1968	1.10188
1969	0.99349
1970	1.09873
1971	1.18594
1972	1.10024
1973	0.96899
1974	0.93429
1975	0.95238
1976	1.07257
1977	1.15156
1978	1.24094
1979	1.15465
1980	1.49175
1981	3.11282
1982	5.01794
1983	4.7061
1984	2.94048
1985	2.95431
1986	2.89536
1987	2.28721
1988	2.40778
1991	7.18391
1992	10.13423
1993	18.98379
1994	29.72769
2004	0.67032
2005	1.45909
2006	0.6498
2007	0.4717
2008	0.45963
2009	0.62269
2010	0.65429
2011	0.85874
2012	0.87462
2013	0.77634
2014	0.72186
2015	0.72758
2016	0.69534
2017	0.63815