Year	%
1997	14.46
1998	13.94
1999	13.56
2000	13.87
2001	12.44
2002	9.04
2003	8.66
2004	8.23
2005	9.24
2006	9.95
2007	11.38
2008	11.79
2009	12.02
2010	14.19
2011	14.87
2012	15.75
2013	15.78
2015	15.99
2016	16.33
2017	16.43
2018	14.96
2019	14.32
2020	13.26
2021	13.14