Year	%
1981	9.6
1989	10
1992	10.2
1995	10.3
1996	10.4
1997	10.1
1998	9.9
2000	9.7
2001	9.1
2002	8.9
2003	9
2004	8.8
2005	9.1
2006	8.8
2007	8.7
2008	9
2009	9
2010	9.2
2011	9.8
2012	10.4
2013	10.3
2014	10.4
2015	10.4
2016	10.5
2017	10.6
2018	10.4
2019	10.4
2020	10.3
2021	10.2
2022	10.3