Year Number 1996 1.26643979549408 1998 1.2458621263504 2000 1.22314357757568 2002 1.42246282100677 2003 1.4146842956543 2004 1.41426146030426 2005 1.35916078090668 2006 1.3497759103775 2007 1.37826728820801 2008 1.39858841896057 2009 1.40567350387573 2010 1.38942682743073 2011 1.61142528057098 2012 1.56186008453369 2013 1.5587409734726 2014 0.880748271942139 2015 0.898378431797028 2016 0.860476732254028 2017 1.1999214887619 2018 1.18732905387878 2019 1.22192621231079 2020 1.33542132377625 2021 1.35934960842133 2022 1.39833402633667