Year	Percent
1987	0.31862
1988	1.98353
1989	3.85205
1990	0.73713
1991	0.38747
1992	0.38293
1993	0.41922
1994	0.76394
1995	1.18583
1996	0.95936
1997	0.91735
1998	4.33467
1999	6.1899
2000	4.6355
2001	3.72506
2002	8.61724
2003	3.37794
2004	9.32006
2005	43.39825
2006	18.48364
2007	20.71992
2008	21.14899
2009	23.05462
2010	7.5836
2011	-0.64281
2012	9.46048
2013	15.7017
2014	38.14478
2015	65.37751
2016	33.52425
2017	-12.81855