Year	number
2005	26.944444444444443
2006	26.88888888888889
2007	24.75
2008	24.4
2009	24.4
2010	23.75
2011	23.15
2012	21.952380952380953
2013	21.428571428571427
2014	21.476190476190474
2015	21.476190476190474
2016	21.285714285714285
2017	20.80952380952381
2018	20.666666666666668
2019	19.476190476190474