Year	%
1991	6.45
1992	10.55
1994	11.64
1995	11.91
1996	11.19
1997	11.31
1998	11.18
1999	10.68
2000	10.96
2001	10.83
2002	11.28
2003	11.06
2004	9.77
2005	9.62
2006	8.75
2007	8.82
2008	8.72
2009	8.23
2010	9.02
2011	5.51
2012	4.43
2013	4.51
2014	4.21
2015	6.54
2016	6.98
2017	4.4
2018	3.28
2019	2.92
2020	2.4
2021	2.58