Year Number 1998 14.32535 1999 14.14692 2000 13.63545 2001 13.67968 2002 13.53766 2003 13.58042 2004 12.12267 2005 11.95668 2006 11.70767 2007 11.50028 2008 11.37433 2009 11.64981 2010 12.12527 2011 12.2561 2012 12.45239