Year	Percent
1997	12.72699
1998	14.15742
1999	7.0314
2000	11.05616
2001	11.63248
2002	9.99422
2003	26.90252
2004	21.5061
2005	17.57194
2006	14.73887
2007	8.04065
2008	12.89485
2009	3.70232
2010	5.45106
2011	7.51027
2012	5.28556
2013	6.5991
2014	4.50275
2015	6.87864
2016	11.96228
2017	13.36181