Year maximum value in 2004 = 100 2006 32.1479533553 2007 33.1066462927 2008 34.3241460021 2009 30.9489918691 2010 32.5248578449 2011 33.6927649007 2012 33.8492400942 2013 35.7414886178 2014 36.5000823136 2015 35.2271001245 2016 34.3248847961 2017 35.316179019 2018 34.9561709531 2019 36.2423406857 2020 36.813579733 2021 39.7428613638