Year	number
2005	13.8
2006	13.8
2007	13.8
2008	13.8
2009	14
2010	14.2
2011	14.2
2012	14
2013	17.0725
2014	16.822499999999998
2015	17.02875
2016	17.27875
2017	16.985
2018	15.265
2019	14.57375