Year	Percent
1991	4.207
1992	4.023
1993	3.977
1994	3.144
1995	3.136
1996	3.16
1997	3.041
1998	3.152
1999	3.076
2000	2.928
2001	3.181
2002	3.08
2003	2.913
2004	2.92
2005	3.125
2006	4.142
2007	4.358
2008	4.538
2009	4.74
2010	4.014
2011	4.051
2012	4.111
2013	3.841
2014	3.882
2015	3.315
2016	3.109
2017	3.2
2018	3.196
2019	3.193
2020	3.19
2021	3.186
2022	3.183