Year Measure 2000 0.283 2001 0.298 2002 0.306 2003 0.31 2004 0.325 2005 0.346 2006 0.362 2007 0.378 2008 0.393 2009 0.401 2010 0.411 2011 0.422 2012 0.427 2013 0.435 2014 0.441 2015 0.448