Year	Percent
1992	21.50918
1993	21.27846
1994	19.49106
1995	26.73279
1996	22.03399
1997	20.01163
1998	13.56521
1999	8.07116
2000	9.86471
2001	11.22681
2002	8.34105
2003	5.54317
2004	4.98718
2005	2.42879
2006	3.53522
2007	5.40914
2008	4.99507
2009	4.03855
2010	2.32919
2011	2.26863
2012	3.38149
2013	2.93591
2014	3.38094
2015	1.88484
2016	0.95928
2017	3.6656