Year	%
2000	19.3
2001	18.8
2002	17.3
2003	17.6
2004	17.9
2005	18.4
2006	19.1
2007	19.3
2008	20
2009	20.9
2010	21.2
2011	22.2
2012	22.7
2013	23.1
2014	23.5
2015	23.6
2016	23.4
2017	23.6
2018	23.8
2019	23.9