Year	Percent
1991	6.048
1992	5.317
1993	5.268
1994	5.201
1995	5.244
1996	5.158
1997	5.011
1998	4.815
1999	4.632
2000	4.465
2001	4.31
2002	4.052
2003	4.308
2004	4.504
2005	4.269
2006	4.108
2007	4.102
2008	3.997
2009	3.931
2010	4.19
2011	4.114
2012	4.07
2013	4.061
2014	4.159
2015	4.122
2016	4.077
2017	4.173
2018	4.136
2019	4.048
2020	3.905
2021	3.753
2022	3.598