Year	number
2005	15.88679245283019
2006	15.88679245283019
2007	15.87037037037037
2008	15.88888888888889
2009	15.703703703703704
2010	15.74074074074074
2011	15.851851851851851
2012	15.654545454545454
2013	16.037966101694913
2014	16.088813559322034
2015	16.133728813559323
2016	16.273965517241376
2017	16.18172413793103
2018	15.87551724137931
2019	15.676724137931032