Year	%
2003	44.2
2004	41.2
2005	41.3
2006	41.7
2007	39.3
2008	40.1
2009	39.6
2010	39.7
2011	40.3
2012	40.7
2013	42.5
2014	42.1
2015	40.4
2016	39.1
2017	38.4
2018	38.3
2019	38.9
2020	39
2021	39.9