Year Number 1996 1.2536518573761 1998 1.30039668083191 2000 1.55263936519623 2002 1.50557315349579 2003 1.63000345230103 2004 1.61270821094513 2005 1.60232031345367 2006 1.52669358253479 2007 1.50993680953979 2008 1.31083500385284 2009 1.01376235485077 2010 0.920679152011871 2011 1.05194532871246 2012 1.11312413215637 2013 1.13294076919556 2014 1.21289432048798 2015 1.2609771490097 2016 1.26583850383759 2017 1.42281877994537 2018 1.40824568271637 2019 1.36299002170563 2020 1.44301211833954 2021 1.52774238586426 2022 1.30729651451111