Year	%
2000	15.5
2001	15.4
2002	16.2
2003	16.2
2004	15.6
2005	15.8
2006	16
2007	15.8
2008	15.4
2009	15.1
2010	15.1
2011	15.4
2012	21.5
2013	21.6
2014	21.7
2015	22
2016	18.7
2017	19.1
2018	17.9
2019	17.9