Year	Percent
1988	14.99742
1989	21.98939
1990	10.43034
1991	5.61863
1992	6.06314
1993	7.08496
1995	7.23198
1996	9.85591
1997	62.23891
1998	11.65091
1999	11.19631
2000	37.31515
2001	4.45111
2002	55.09142
2003	9.32876
2004	2.99589
2005	7.35686
2006	5.8517
2007	13.62512
2008	4.09129
2009	1.42822
2010	45.95065
2011	7.95516
2012	45.75566
2013	8.04631
2014	4.36131
2015	11.99674
2016	2.24113