Year Measure 1995 2.77 1996 2.69 1997 3.05 1998 3.3 1999 3.6 2000 2.8 2001 2.9 2002 2.6 2003 2.5 2004 2.6 2005 2.5 2006 2.5 2007 2.5 2008 2.3 2009 2.4 2010 2.4 2011 2.6443