Year	Percent
1998	7.65146
1999	5.99704
2000	4.38454
2001	5.5196
2002	5.23384
2003	7.86769
2004	9.13495
2005	18.43134
2006	53.93365
2007	39.46356
2008	17.43969
2009	24.2214
2010	18.01635
2011	11.7
2012	11.31864
2013	11.08385
2014	10.37571
2015	18.92303
2016	29.25532
2017	28.57984