Year	Percent
1991	4.79
1992	5.025
1993	4.734
1994	4.372
1995	4.261
1996	4.005
1997	4.082
1998	4.117
1999	4.24
2000	4.254
2001	4.354
2002	4.548
2003	4.682
2004	4.278
2005	4.299
2006	4.521
2007	4.138
2008	3.8
2009	3.362
2010	3.199
2011	3.335
2012	3.639
2013	3.946
2014	4.125
2015	4.215
2016	4.197
2017	4.262
2018	4.167
2019	3.994
2020	3.805
2021	3.613
2022	3.432