Year	number
2005	13.7
2006	14.34375
2007	14.441176470588236
2008	14.228571428571428
2009	14.17142857142857
2010	14.17142857142857
2011	14.162162162162161
2012	14.289473684210526
2013	14.263157894736842
2014	14.31578947368421
2015	14.31578947368421
2016	14.421052631578947
2017	14.342105263157896
2018	14.342105263157896
2019	14.236842105263158