Year	%
2000	30.8
2001	30.4
2002	29
2003	27.9
2004	26.5
2005	25.2
2006	23.1
2007	22.4
2008	21
2009	19.7
2010	18.5
2011	17.6
2012	16.8
2013	16.4
2014	16.3
2015	16.2
2016	16.2
2017	16.2
2018	16.3
2019	16.4
