Year	Percent
1991	2.517
1992	2.266
1993	2.469
1994	2.914
1995	4.016
1996	4.265
1997	4.205
1998	4.177
1999	4.145
2000	4.023
2001	4.102
2002	3.798
2003	4.12
2004	4.077
2005	4.269
2006	5.1
2007	6.011
2008	5.398
2009	5.86
2010	5.594
2011	5.073
2012	4.797
2013	3.749
2014	3.995
2015	3.818
2016	3.418
2017	3.26
2018	3.167
2019	3.097
2020	3.04
2021	2.987
2022	2.939