Year	%
1997	11
1998	8.49
1999	7.95
2000	7.67
2001	7.41
2002	7.7
2003	7.21
2004	7.22
2005	6.69
2006	7.8
2007	7.78
2008	7.65
2009	6.48
2010	6.32
2011	5.21
2012	5.53
2013	5.41
2015	5.06
2020	4.57
2021	4.4