Year	Percent
1979	7.43
1980	4.82
1982	5.91
1983	5.89
1984	4.81
1985	5.16
1986	5.85
1987	4.34
1988	4.56
1989	5.46
1990	6.36
1991	4.72
1992	3.67
1993	4.38
1994	3.72
1995	3.7
1996	8.6
1997	6.83
2000	8.88
2002	11.8008
2003	8.3243
2004	8.3582
2005	6.2513
2006	6.6504
2007	6.6126
2008	5.9614
2009	6.6484
2010	6.0499
2011	6.3569
2012	5.4321
2013	4.9547
2014	6.7621
2015	4.9337
2016	6.7064
2017	5.4237