Year	Percent
1992	3.91573
1993	5.98379
1994	6.9129
1995	6.13622
1996	6.01107
1997	5.50026
1998	4.59538
1999	3.38195
2000	2.86604
2001	1.96148
2002	2.09708
2003	2.36598
2004	2.24695
2005	1.41986
2006	1.15943
2007	1.14926
2008	1.70919
2009	4.53643
2010	6.33568
2011	7.00522
2012	8.52798
2013	9.25584
2014	8.55988
2015	7.22922
2016	5.90867
2017	4.77659