Year Percent 1995 3.532 1996 3.841 1997 3.997 1998 3.735 1999 3.496 2000 3.395 2001 3.316 2002 3.7 2003 3.575 2004 3.506 2005 3.544 2006 3.491 2007 3.562 2008 3.97 2009 4.172 2010 3.883