Year	%
1991	14.52
1993	9.91
1996	7.7
1997	7.58
1998	6.91
1999	6.73
2000	6.53
2001	5.91
2002	5.61
2003	5.64
2004	5.7
2005	4.65
2006	4.19
2007	4.27
2008	4.27
2009	4.42
2010	3.07
2011	3.02
2012	2.99
2013	3.01
2014	3.07
2015	2.67
2016	2.46
2017	2.38
2018	2.36
2019	2.15
2020	2.09
2021	2.05