Year Measure 1995 4.1 1996 3.54 1997 3.21 1998 3.4 1999 3.6 2000 3.8 2001 3.6 2002 3.2 2003 3.1 2004 3.2 2005 3.5 2006 3.8 2007 4.1 2008 4.6 2009 4.4 2010 4.4 2011 4.20686