Year	Percent
1983	6.3162
1985	4.4595
1987	6.923
1988	7.835
1989	6.693
1990	6.3156
1991	5.0731
1992	5.2549
1993	5.091
1994	4.8715
1995	3.2193
1996	5.0887
1997	5.476
1998	3.5341
1999	3.9014
2000	2.135
2001	1.1166
2002	1.5993
2003	2.0729
2004	3.1132
2005	3.5903
2006	3.4305
2007	3.2114
2008	2.9564
2009	2.8695
2010	3.7116
2011	4.854
2012	5.1669
2013	6.1778
2014	7.2475
2015	7.5914
2016	7.4187
2017	5.8442