Year	1=low to 6=high
2005	3.1013157894736847
2006	3.071794871794872
2007	3.0813333333333337
2008	3.084
2009	3.103896103896105
2010	3.109090909090908
2011	3.1128205128205124
2012	3.0862499999999993
2013	3.0753086419753086
2014	3.061842105263157
2015	3.0565789473684197
2016	3.0424657534246564
2017	3.012162162162162
2018	3.0260273972602736
2019	3.0066666666666655
2020	2.9863013698630128
2021	2.984722222222222
2022	2.951351351351352
2023	2.9432432432432436