Year	Percent
1992	17.30374
1993	6.52369
1994	10.74062
1995	10.18208
1996	10.72183
1997	10.03985
1998	5.64637
1999	4.52343
2000	6.61435
2001	7.17221
2002	7.41683
2003	34.07032
2004	3.47794
2005	3.02023
2006	2.46816
2007	2.21941
2008	2.6194
2009	5.37788
2010	6.98315
2011	5.3991
2012	26.75342
2013	30.92868
2014	20.85176
2015	33.75109
2016	28.45179