Year	%
2000	41.8
2001	39.4
2002	41.2
2003	41.5
2004	40.2
2005	41
2006	40.8
2007	41.2
2008	38.7
2009	38.1
2010	36.2
2011	37.1
2012	35.5
2013	34.3
2014	35
2015	33.1
2016	30.1
2017	29.3
2018	27.9
2019	26.5