Year	Percent
1990	0.17556
1991	0.40274
1992	1.08447
1993	2.43286
1994	2.72069
1995	3.93632
1996	4.3916
1997	3.57551
1998	3.31925
1999	4.15591
2000	4.69807
2001	5.20965
2002	4.40736
2003	3.55984
2004	4.32128
2005	2.88043
2006	2.27397
2007	1.8656
2008	1.65887
2009	4.70316
2010	7.41645
2011	5.20259
2012	4.17933
2013	3.08224
2014	2.93346
2015	1.94508
2016	2.04733
2017	1.82383