Year	Percent
1985	1.43167
1986	0.46856
1987	1.27812
1988	2.82927
1989	5.04265
1990	2.86329
1991	3.73839
1992	6.41671
1993	5.9429
1994	6.82982
1995	7.68483
1996	7.65961
1997	6.64316
1998	4.41692
1999	3.53507
2000	5.59796
2001	5.07474
2002	5.26149
2003	5.87698
2004	6.53219
2005	6.55077
2006	5.99011
2007	6.13794
2008	4.6647
2009	4.36564
2010	5.33209
2011	5.09503
2012	4.06606
2013	4.21688
2014	4.7844
2015	5.50882
2016	5.09051
2017	5.72588