Year	Percent
1974	8.9
1982	6
1986	10.92
1987	10.26
1990	6.12
1991	5.54
1992	2.93
1995	3.4
1996	4.42
1997	3.32
1998	4.35
1999	3.89
2001	4.08
2002	4.81
2003	6.55
2004	8.31
2005	6.3829
2006	4.3936
2007	4.2831
2008	3.8397
2009	4.2592
2010	5.3982
2011	6.3069
2012	5.1196
2013	5.0848
2014	6.9
2015	6.3331
2016	5.5036
2017	5.5133