Year % 1997 98.03708 1998 100 1999 99.49111 2000 100 2001 99.54809 2002 100 2003 99.29419 2004 98.85834 2005 100 2006 99.53537 2007 100 2008 99.53915 2009 100 2010 99.48526 2011 99.33097