Year	Percent
1979	4.59
1980	3.61
1982	5.41
1983	9.79
1984	9.12
1985	5.11
1986	6.3
1987	6.46
1988	4.84
1989	6.21
1990	6.13
1991	5.36
1992	5.96
1993	5.57
1994	4.89
1995	3.1
1996	7.82
1997	4.53
2000	6.78
2002	7.9091
2003	5.8537
2004	5.2653
2005	3.8761
2006	4.4005
2007	3.4329
2008	3.4196
2009	4.6744
2010	3.619
2011	3.4936
2012	3.1024
2013	3.9666
2014	3.8191
2015	4.2851
2016	4.2601
2017	4.0605