Year	%
1991	24.92044
1995	22.69389
1996	25.93653
1997	29.54929
1998	28.67967
1999	18.20416
2000	47.12137
2001	47.17282
2002	36.61349
2003	47.10548
2004	25.59455
2005	16.06503
2006	16.02752
2007	16.91023
2008	18.64906
2009	17.51911
2010	22.87628
2011	26.99759
2012	26.69915
2013	22.90359
2014	13.31193
2015	21.98239
2016	25.43296
2017	14.81057
2018	11.50292