Year	%
1985	9.7
1988	9.6
1992	9.5
1995	8.6
1997	9
2000	8.4
2003	8.5
2004	8.4
2005	8.7
2006	8.7
2007	8.6
2008	8.7
2009	8.5
2010	8.6
2011	8.6
2012	8.7
2013	8.6
2014	8.6
2015	8.6
2016	8.6
2017	8.7
2018	8.9
2019	9
2020	9.4
2021	9.2