Year	Percent
1983	1.6564
1984	1.4379
1985	1.4961
1986	1.2728
1987	1.4196
1988	1.0248
1989	0.9105
1990	1.0416
1991	0.9236
1992	1.193
1993	1.5957
1994	2.4886
1995	1.7263
1996	1.809
1997	1.5466
1998	1.6831
1999	1.3791
2000	1.4399
2001	1.1143
2002	1.7523
2003	2.6081
2004	3.2663
2005	2.8694
2006	2.7369
2007	2.8438
2008	3.8043
2009	3.4816
2010	3.0264
2011	3.3021
2012	3.7997
2013	4.5841
2014	4.6654
2015	4.9664
2016	4.9547
2017	4.8153