Year	%
1985	22.8
1988	22.7
1992	23
1995	22.5
1997	22.7
2000	20.8
2003	22.7
2004	21.9
2005	22.2
2006	22.7
2007	22.3
2008	22.7
2009	22.7
2010	22.5
2011	22.7
2012	22.8
2013	23
2014	22.8
2015	22.7
2016	22.7
2017	22.7
2018	22.4
2019	22.3
2020	22.6
2021	22.4