Year Measure 1992 39.441 1993 41.30302 1994 45.69846 1995 47.89398 1996 54.2296 1997 58.5193 1998 50.55482 1999 53.29678 2000 50.69558 2001 55.47416 2002 59.757 2003 62.32838 2004 60.90256 2005 60.97243 2006 57.04944 2007 58.98878 2008 57.17477 2009 60.32015 2010 61.94714 2011 64.13852