Year	Percent
1990	0.22575
1991	0.48331
1992	1.18204
1993	2.34697
1994	2.92678
1995	2.33084
1996	3.19179
1997	3.10289
1998	3.08241
1999	2.12236
2000	1.50277
2001	1.01538
2002	1.15647
2003	1.24864
2004	1.6147
2005	0.34533
2006	0.91909
2007	1.07194
2008	0.99184
2009	1.66643
2010	1.95902
2011	1.73138
2012	1.79213
2013	1.75949
2014	1.72717
2015	1.6325
2016	1.55457
2017	1.50841