Year	%
1977	2.8
1978	2.7
1979	2.7
1980	3
1981	3.1
1982	3.4
1983	3.2
1984	3
1986	3
1987	2.4
1989	3.1
1991	3
1993	2
1995	2.1
1998	1.8
2000	2.1
2002	2.2
2003	2.3
2004	2.4
2005	2.4
2006	2.5
2007	2.5
2008	2.4
2009	2.3
2010	2.1
2011	2.1
2012	2
2013	2
2014	2
2015	1.7
2016	1.9
2017	1.9
2018	1.9
2019	2.1
2020	2.1
2021	2.3