Year Number 1996 1.46238899230957 1998 1.42910289764404 2000 1.49271559715271 2002 1.47299218177795 2003 1.55566942691803 2004 1.62832796573639 2005 1.568608045578 2006 1.44533681869507 2007 1.43100023269653 2008 1.4256500005722 2009 1.41521406173706 2010 1.44575238227844 2011 1.41072964668274 2012 1.44295036792755 2013 1.43956887722015 2014 1.35735297203064 2015 1.37652158737183 2016 1.35611021518707 2017 1.37918603420258 2018 1.38901424407959 2019 1.30208480358124 2020 1.3812929391861 2021 1.36291229724884 2022 1.42238974571228