Year	%
1997	15.2
2000	12.05
2001	11.6
2002	8.66
2003	8.44
2004	7.49
2005	7.64
2006	6.72
2007	6.15
2008	5.25
2009	4.72
2010	4.82
2011	4.66
2012	2.92
2013	2.95
2014	2.81
2015	2.77
2016	2.91
2017	2.56
2018	2.61
2019	2.61
2020	2.76
2021	2.75