Year	Percent
1991	4.85259
1992	4.81339
1993	4.76533
1994	4.70976
1995	4.6482
1996	4.58018
1997	4.49712
1998	4.40549
1999	4.30114
2000	4.18606
2001	4.05786
2002	3.93042
2003	4.03326
2004	4.11429
2005	3.97778
2006	3.8457
2007	3.7159
2008	3.59665
2009	3.48
2010	3.37876
2011	3.2807
2012	3.18167
2013	3.08148
2014	2.98079
2015	2.88141
2016	2.77976
2017	2.67677
2018	2.57356
2019	2.46199