Year	%
1996	22.7
1997	22.8
1998	22.2
1999	22.5
2000	22.4
2001	22.1
2002	22.4
2003	23
2004	23.1
2005	22.8
2006	22.8
2007	22.4
2008	22.3
2009	22.5
2010	22.5
2011	22.3
2012	22.4
2013	22.5
2014	22.3
2015	22.6
2016	22.2
2017	22.4
2018	22.6
2019	22.4
2020	22.9
2021	22.5