Year	%
2000	30.8
2001	30.2
2002	28.9
2003	27.8
2004	26.3
2005	24.8
2006	22.7
2007	21.4
2008	20
2009	19
2010	18.2
2011	17.6
2012	17.1
2013	16.8
2014	16.6
2015	16.4
2016	16.3
2017	16.2
2018	16.1
2019	16.1