Year	%
1985	9.6
1986	9.2
1987	8.8
1988	9.1
1989	9
1990	9.4
1991	9.3
1992	9.4
1993	9.6
1994	9
1995	9
1996	8.6
1997	8.6
1998	8.3
1999	8.4
2000	8.5
2001	8.4
2002	8.6
2003	8.3
2004	8.3
2005	8.2
2006	8.2
2007	8.3
2008	7.8
2009	8
2010	8.2
2011	7.8
2012	7.3
2013	7.6
2014	7.9
2015	7.4
2016	7.6
2017	6.8
2018	6.6
2019	7.2
2020	7.1
2021	7.2