Year	%
1963	5.6
1964	5.6
1965	5.7
1966	5.5
1967	5.8
1968	6
1969	6.1
1970	5.9
1971	5.9
1972	5.8
1973	5.9
1974	6.1
1975	6
1976	6.1
1977	6.2
1978	6.2
1979	6.4
1980	6.4
1981	6.2
1982	5.8
1983	5.5
1984	5.6
1985	5.6
1986	5.5
1987	5.6
1988	5.6
1989	5.6
1990	5.6
1991	5.6
1992	5.5
1993	5.2
1994	5.4
1995	5.5
1996	5.5
1997	5.4
1998	5.4
1999	5.5
2000	5.5
2001	5.4
2002	5.3
2003	5.2
2004	5.3
2005	5.3
2006	5.2
2007	5.2
2008	5.2
2009	5.4
2010	5.3
2011	5.2
2012	5.2
2013	5.3
2014	5.2
2015	5.3
2016	5.2
2017	5.2
2018	5.2
2019	5.1
2020	5.6
2021	6