Year	Percent
1988	0.07372
1989	0.13212
1990	0.00023
1991	0.0002
1992	0.26448
1993	0.48049
1994	1.10846
1995	2.28224
1996	2.31007
1997	2.05476
1998	1.8438
1999	5.32799
2000	4.54949
2001	5.28981
2002	3.66076
2003	2.73092
2004	3.45039
2005	5.52582
2006	2.16566
2007	2.70449
2008	5.05423
2009	3.33393
2010	5.77307
2011	3.62872
2012	4.60412
2013	4.6996
2014	3.4686
2015	3.51701
2016	2.88127
2017	2.26606