Year % 1998 61.12916 1999 60.93655 2000 62.28268 2001 65.32729 2002 67.79238 2003 68.15734 2004 67.96352 2005 68.64702 2006 71.11364 2007 71.35227 2008 72.45075 2009 73.047 2010 72.57424 2011 74.52499 2012 73.17187 2013 74.80471 2014 73.50754 2015 76.04809 2016 74.73641 2017 76.40604