Year	Percent
1991	5.25343
1992	5.25174
1993	5.45761
1994	5.43145
1995	4.33814
1996	4.99196
1997	3.83885
1998	3.52783
1999	4.0204
2000	4.10134
2001	4.19
2002	3.70148
2003	2.98833
2004	4.41517
2005	3.47655
2006	2.49204
2007	2.29407
2008	2.91854
2009	2.8601
2010	2.68402
2011	2.62649
2012	2.60186
2013	2.55585
2014	2.47391
2015	2.41717
2016	2.35102
2017	2.30434
2018	2.23849
2019	2.17761