Year	%
2000	23.9
2001	23.8
2002	23.6
2003	23.2
2004	22.8
2005	22.7
2006	22.6
2007	22.3
2008	22.2
2009	22.1
2010	21.9
2011	22.3
2012	22
2013	21.9
2014	21.7
2015	21.6
2016	21.6
2017	21.5
2018	21.5
2019	21.4