Year maximum value in 2004 = 100 2006 3.7656103003 2007 3.7343895292 2008 3.4648584932 2009 4.8143168917 2010 5.4022155602 2011 4.511415658 2012 5.4624683043 2013 4.971616732 2014 6.2252675568 2015 5.9957638583 2016 5.937048009 2017 5.6006432522 2018 5.2008142797 2019 6.8665725873 2020 6.5424039905 2021 6.8470104079