Year	Percent
1991	6.429
1992	4.107
1993	4.097
1994	4.249
1995	4.386
1996	4.146
1997	4.175
1998	3.869
1999	3.883
2000	4.089
2001	4.226
2002	4.868
2003	4.757
2004	5.201
2005	4.661
2006	4.698
2007	4.462
2008	4.355
2009	4.224
2010	4.317
2011	4.673
2012	4.427
2013	4.37
2014	4.288
2015	4.03
2016	3.75
2017	3.558
2018	3.554
2019	3.55
2020	3.545
2021	3.541
2022	3.536