Year	Percent
1991	5.7832
1992	5.5136
1993	5.51403
1994	5.25619
1995	5.45571
1996	5.38165
1997	5.08642
1998	4.73735
1999	4.59832
2000	4.29036
2001	4.08644
2002	3.94838
2003	3.82942
2004	3.5845
2005	3.29983
2006	3.25154
2007	2.86402
2008	2.64053
2009	2.70008
2010	2.54825
2011	2.36875
2012	2.22709
2013	2.2074
2014	2.24979
2015	2.00986
2016	2.08974
2017	2.06319
2018	2.10489
2019	2.04029