Year	Percent
1999	3.24
2000	3.2237
2001	3.8557
2002	3.6956
2003	4.1283
2004	4.36
2005	4.8468
2006	4.7924
2007	6.7455
2008	5.7447
2009	4.0322
2010	4.0374
2011	3.097
2012	2.7494
2013	2.0238
2014	1.6751
2015	2.2393
2016	1.809
2017	2.0164