Year	%
1997	2.4
1998	2.2
1999	2.3
2000	2.7
2001	2.6
2002	2.8
2003	3.1
2004	3
2005	2.8
2006	2.8
2007	3
2008	2.9
2009	3.1
2010	3.3
2011	3.5
2012	3.8
2013	3.9
2014	4.2
2015	4.1
2016	4.3
2017	4.3
2018	4.4
2019	4.3
2021	4.3