Year	Percent
1986	4.8947
1987	4.4285
1988	5.6668
1989	7.1038
1990	7.459
1991	9.774
1992	9.736
1993	8.964
1994	7.811
1995	6.488
1996	6.248
1997	6.861
1998	7.613
1999	6.693
2000	5.978
2001	5.382
2002	5.469
2003	5.1101
2004	4.519
2005	4.145
2006	4.198
2007	3.965
2008	4.263
2009	6.143
2010	6.928
2011	6.759
2012	7.387
2013	6.963
2014	6.535
2015	5.8614
2016	5.474
2017	5.198