Year	Percent
1976	0.272
1977	0.24565
1978	0.17214
1979	0.05258
1980	0.00923
1981	0.14083
1982	0.08872
1983	0.07871
1984	0.11408
1985	0.23286
1986	0.39779
1987	0.42174
1988	0.51487
1989	0.45901
1990	0.28226
1991	0.3622
1992	0.20806
1993	0.15224
1994	0.17757
1995	0.31931
1996	0.3888
1997	0.51017
1998	1.44621
1999	1.92343
2000	2.04927
2001	1.22358
2002	0.899
2003	1.03009
2004	1.7381
2005	1.51906
2006	0.90551
2007	0.78624
2008	1.11627
2009	1.00028
2010	0.86774
2011	0.81275
2012	0.77657
2013	0.97783
2014	0.65708
2015	0.2968
2016	0.85555
2017	1.11402