Year	Percent
1985	1.27029
1986	1.57716
1987	5.39148
1988	5.70026
1989	5.36936
1990	7.37404
1991	7.26478
1992	9.12929
1993	4.07495
1994	4.02399
1995	3.04103
1996	4.52471
1997	5.57391
1998	4.67632
1999	2.73385
2000	2.76737
2001	3.10267
2002	2.09385
2003	1.98114
2004	1.94434
2005	2.00809
2006	1.86918
2007	1.67699
2008	1.63001
2009	1.81701
2010	1.86844
2011	1.74902
2012	1.65716
2013	1.6001
2014	1.53517
2015	1.67634
2016	1.60081
2017	1.87958