Year	Percent
1983	7.9848
1984	5.5355
1985	6.5227
1986	6.6662
1987	6.5982
1988	4.7923
1989	3.859
1990	4.4243
1991	2.5409
1992	3.1044
1993	4.2709
1994	7.2479
1995	7.809
1996	8.2666
1997	9.188
1998	7.0922
1999	7.4015
2000	7.2883
2001	5.4402
2002	8.9787
2003	12.1892
2004	22.4817
2005	16.1909
2006	15.1533
2007	17.4731
2008	24.0807
2009	17.7773
2010	10.1949
2011	20.7961
2012	18.6302
2013	10.9222
2014	18.094
2015	15.6643
2016	18.0355
2017	13.2473