Year	%
2000	43.1
2001	41.8
2002	40.7
2003	40.9
2004	39.6
2005	40.3
2006	40.6
2007	40.9
2008	41
2009	40.1
2010	39.6
2011	39.3
2012	39
2013	38.8
2014	38.7
2015	38.5
2016	38.3
2017	38.1
2018	37.9
2019	37.7