Year	Percent
1991	4.022
1992	3.997
1993	3.795
1994	3.848
1995	3.804
1996	3.777
1997	3.671
1998	3.611
1999	3.41
2000	2.569
2001	2.364
2002	2.398
2003	2.343
2004	2.296
2005	2.21
2006	2.177
2007	2.082
2008	2.165
2009	2.22
2010	2.309
2011	2.325
2012	2.185
2013	2.143
2014	2.2
2015	2.341
2016	2.318
2017	2.325
2018	2.289
2019	2.265
2020	2.245
2021	2.227
2022	2.209