Year	%
2000	12.9
2001	11
2002	12.3
2003	12.6
2004	12
2005	14.5
2006	17.1
2007	17
2008	16.8
2009	16.9
2010	17
2011	19.7
2012	10.5
2013	10
2014	9.7
2015	10
2016	8.3
2017	7.5
2018	6.7
2019	6