Year	%
2000	29.8
2001	29
2002	28.3
2003	27.7
2004	27
2005	26.5
2006	25.8
2007	25.1
2008	24.4
2009	24
2010	23.5
2011	22.9
2012	22.5
2013	22.2
2014	22.2
2015	22.2
2016	22.1
2017	22.2
2018	22.2
2019	22.3