Year	Percent
1983	7.9908
1984	9.9554
1985	10.4292
1986	10.1725
1987	12.3141
1988	11.691
1989	11.2
1990	9.4588
1991	9.3644
1992	8.4066
1993	8.4774
1994	8.5099
1995	7.4366
1996	6.7075
1997	6.4731
1998	5.2579
1999	4.1683
2000	2.5991
2001	2.6263
2002	2.4319
2003	2.5653
2004	2.8815
2005	2.9991
2006	2.4202
2007	2.4296
2008	3.6044
2009	7.5434
2010	10.1344
2011	11.3935
2012	12.7212
2013	11.8776
2014	10.4997
2015	8.7152
2016	7.1291
2017	5.809