Year	Percent
1997	3.28914
1998	3.05272
1999	2.6001
2000	2.34488
2001	2.48919
2002	2.3816
2003	2.13574
2004	2.41925
2005	2.83378
2006	2.76376
2007	2.23644
2008	2.44032
2009	4.53291
2010	12.79652
2011	2.38181
2012	2.00602
2013	2.21437
2014	2.06917
2016	2.37167