Year Number 1996 8.50278 1998 9.69223 1999 8.0438 2001 8.14641 2002 7.86701 2003 9.24547 2004 9.26543 2005 12.70319 2006 8.64478 2008 8.75561 2009 8.10228 2010 9.0863 2012 9.45972 2013 9.20151 2014 9.5617 2015 9.97832 2016 9.50427 2017 9.56785 2018 10.37184