Year	Percent
1983	5.5624
1984	5.1182
1985	6.4043
1986	5.4862
1987	4.2465
1988	4.6424
1989	2.8684
1990	2.8313
1991	2.7105
1992	4.2127
1993	4.4277
1994	8.4899
1995	6.7381
1996	10.0797
1997	5.5984
1998	5.8211
1999	6.1961
2000	5.6602
2001	7.1127
2002	5.3378
2003	9.73
2004	12.0935
2005	11.7424
2006	17.0109
2007	13.5379
2008	12.5281
2009	16.665
2010	17.6452
2011	13.3404
2012	18.8666
2013	18.7425
2014	26.0667
2015	18.8783
2016	19.7057
2017	17.1808