Year Measure 1995 2.16 1996 2.43 1997 2.88 1998 3.5 1999 3.4 2000 3.1 2001 3.5 2002 3.5 2003 3.4 2004 3.4 2005 3.2 2006 3.3 2007 3.5 2008 3.6 2009 3.6 2010 3.5 2011 3.63557