Year maximum value in 2004 = 100 2006 3.2025611964 2007 3.7064667277 2008 2.8162541055 2009 5.8891523872 2010 5.7339346195 2011 7.742012996 2012 7.9466700817 2013 7.0697483499 2014 1.8304445435 2015 7.4208112011 2016 7.2503269496 2017 7.0843511845 2018 6.9125847988 2019 7.0671868982 2020 7.2153847386 2021 7.3078393345