Year	Percent
1983	7.5912
1984	7.1892
1985	5.5197
1986	3.9854
1987	4.3188
1988	5.3334
1989	7.0023
1990	7.5088
1991	7.9159
1992	7.7497
1993	10.0601
1994	6.6904
1995	4.9584
1996	4.6719
1997	4.0509
1998	3.2492
1999	3.7065
2000	3.5247
2001	2.9052
2002	3.3056
2003	4.4301
2004	4.3536
2005	3.6799
2006	2.4216
2007	2.7028
2008	2.4677
2009	5.7446
2010	7.2646
2011	6.3342
2012	6.633
2013	5.7376
2014	5.3789
2015	5.3933
2016	4.7973
2017	4.928