Year	Percent
1991	5.46102
1992	5.27141
1993	5.14439
1994	5.0454
1995	4.3944
1996	3.87717
1997	3.73696
1998	3.7066
1999	3.32164
2000	3.6682
2001	3.54831
2002	3.21287
2003	3.29494
2004	3.27169
2005	3.18249
2006	3.0883
2007	2.9638
2008	2.71019
2009	2.76175
2010	2.54748
2011	2.39939
2012	2.63987
2013	2.59627
2014	2.48436
2015	2.49707
2016	2.33599
2017	2.1128
2018	2.19632
2019	2.22925