Year	Percent
1988	1.41
1991	2.524
1992	2.674
1993	2.879
1994	3.972
1995	6.042
1996	4.446
1997	2.968
1998	2.874
1999	1.949
2000	2.192
2001	2.15
2002	2.5681
2003	2.9156
2004	3.2029
2005	3.3589
2006	3.3775
2007	3.4072
2008	3.7782
2009	5.3582
2010	5.3745
2011	5.1943
2012	4.8928
2013	4.8883
2014	4.7865
2015	4.2275
2016	3.8284
2017	3.3092