Year	Percent
1983	4.72888
1984	4.35757
1985	3.663
1986	4.57004
1987	2.94538
1988	5.25362
1989	3.93529
1990	1.97507
1992	1.87713
1993	2.67922
1994	1.87758
1995	1.38562
1996	1.54464
1997	1.07587
1998	0.92296
1999	1.36522
2000	1.54143
2001	1.53232
2002	1.72526
2003	1.49629
2004	1.14479
2005	0.83488
2006	3.00446
2007	4.50461
2008	5.90634
2009	7.98508
2010	5.77816
2011	5.01552
2013	5.60983
2014	2.81837
2015	2.02945
2016	3.22518
2017	2.15136