Year	Percent
1991	0.989
1992	1.032
1993	1.195
1994	2.047
1995	3.86
1996	2.804
1997	0.992
1998	1.322
1999	1.145
2000	1.548
2001	1.404
2002	1.4801
2003	1.6955
2004	1.8657
2005	2.3203
2006	2.1333
2007	2.3378
2008	2.6173
2009	3.6051
2010	3.8143
2011	3.5205
2012	3.2764
2013	3.3338
2014	3.2349
2015	2.9371
2016	2.4964
2017	2.2799