Year	Measure
1998	4.2
1999	4.1
2000	3
2001	2.9
2002	2.7
2003	2.3
2004	2.3
2005	2.6
2006	2.4
2007	2.1
2008	1.8
2009	2.2
2010	2.4
2011	2.22977