Year	Percent
2000	3.89971
2001	2.91958
2002	2.91446
2003	2.67356
2004	2.36475
2005	2.22477
2006	2.08075
2007	2.1026
2008	6.3056
2009	6.57755
2010	7.12352
2011	7.28696
2012	7.26738
2013	7.20959
2014	7.3409
2015	7.52283
2016	8.13132
2017	8.57288