Year	Percent
1983	7.6952
1984	11.1841
1985	9.9369
1986	12.1577
1987	11.5584
1988	12.3021
1989	11.0828
1990	9.6308
1991	9.5697
1992	8.1785
1993	7.3497
1994	8.1432
1995	8.698
1996	6.9425
1997	5.3043
1998	4.5027
1999	4.465
2000	2.37
2001	2.6778
2002	2.2338
2003	1.9743
2004	1.5096
2005	2.4276
2006	2.4149
2007	2.5449
2008	3.1228
2009	4.9477
2010	6.7147
2011	7.1776
2012	7.5163
2013	9.2844
2014	8.1784
2015	6.3759
2016	5.4116
2017	5.6464