Year 1=low to 6=high 2005 3.1315789473684212 2006 3.1578947368421053 2007 3.236842105263158 2008 3.236842105263158 2009 3.225 2010 3.25 2011 3.375 2012 3.425 2013 3.425 2014 3.375 2015 3.375 2016 3.475 2017 3.525 2018 3.55 2019 3.55 2020 3.55 2021 3.575 2022 3.6 2023 3.6