Year	%
1986	21.4
1989	19.9
1992	18.9
1996	20.7
1997	20.6
2000	20.1
2001	19.9
2002	20.6
2003	19.3
2004	19.2
2005	19.9
2006	19.4
2007	19.8
2008	20.2
2009	19.8
2010	20.8
2011	20.6
2012	20.6
2013	19.9
2014	21.5
2015	20.9
2016	20.8
2017	20.6
2018	20.4
2019	21
2020	21.7
2021	21.5
2022	22.3