Year	Percent
1991	3.49137
1992	3.45143
1993	3.4825
1994	3.34797
1995	3.15368
1996	3.11251
1997	3.00698
1998	2.99068
1999	2.80592
2000	2.51556
2001	2.16039
2002	2.11691
2003	2.10716
2004	2.02318
2005	2.1217
2006	2.11212
2007	2.00069
2008	1.94061
2009	1.9543
2010	1.80731
2011	1.7879
2012	1.7529
2013	1.7749
2014	1.714
2015	1.6434
2016	1.57957
2017	1.5186
2018	1.4867
2019	1.5118