Year	%
2000	30.8
2001	30.3
2002	30
2003	30.2
2004	28.2
2005	28.6
2006	27.2
2007	27.5
2008	27.6
2009	26.8
2010	25.6
2011	24.9
2012	24.5
2013	23.2
2014	23
2015	24.1
2016	23.2
2017	22.8
2018	22.2
2019	21.8