Year	%
2000	41.7
2001	38.5
2002	35.7
2003	32.9
2004	30.5
2005	28.6
2006	27.4
2007	26.6
2008	25.7
2009	24.6
2010	24
2011	23.4
2012	23
2013	22.6
2014	22.6
2015	22.4
2016	22.1
2017	22
2018	22
2019	22