Year	%
2000	44.4
2001	44
2002	43.5
2003	43.1
2004	42.5
2005	41.9
2006	41.5
2007	41.1
2008	40.7
2009	40.3
2010	40
2011	39.8
2012	39.6
2013	39.5
2014	39.4
2015	39.4
2016	39.4
2017	39.3
2018	39.3
2019	39.3