Year	%
2000	41.7
2001	42.1
2002	42.1
2003	41.5
2004	41.4
2005	40.9
2006	40.5
2007	40.1
2008	39.4
2009	38.4
2010	37.8
2011	37.1
2012	36.6
2013	36.2
2014	35.7
2015	35.6
2016	35.6
2017	35.5
2018	35.4
2019	35.3