Year maximum value in 2004 = 100 2006 11.4054570385 2007 11.006240827 2008 11.2900551948 2009 12.7693677522 2010 11.9371671727 2011 13.2121436296 2012 14.1036154 2013 15.7335421005 2014 17.017950773 2015 17.636388968 2016 17.6330366094 2017 18.1177787252 2018 18.8513912953 2019 17.9510312217 2020 18.4002866426 2021 19.1385509278