Year maximum value in 2004 = 100 2006 12.645974846 2007 12.3310106699 2008 10.6427052435 2009 11.800751538 2010 12.2283306725 2011 14.0512156754 2012 13.1727189985 2013 15.1680140495 2014 13.8426477693 2015 18.1086815554 2016 15.4285168573 2017 14.7162272078 2018 16.9878829883 2019 16.0268081861 2020 15.6559319296 2021 15.8095346846