Year maximum value in 2004 = 100 2006 4.9558082375 2007 5.2128647216 2008 4.9756422445 2009 5.592264539 2010 6.9532069794 2011 8.2892619921 2012 8.6087715517 2013 8.2783480707 2014 10.1280217884 2015 6.2920873161 2016 11.1425217301 2017 11.1657843484 2018 11.6158113538 2019 11.6888922406 2020 11.661401132 2021 11.7972761592