Year 1=low to 6=high 2005 3.1052631578947367 2006 3.1052631578947367 2007 3.1052631578947367 2008 3.0789473684210527 2009 3.15 2010 3.275 2011 3.375 2012 3.35 2013 3.35 2014 3.275 2015 3.25 2016 3.225 2017 3.25 2018 3.325 2019 3.375 2020 3.4 2021 3.45 2022 3.55 2023 3.55