Year	number
2004	6.857142857142857
2005	6.75
2006	6.8
2007	6.75
2008	6.75
2009	6.75
2010	6.75
2011	6.75
2012	6.8
2013	7.194090909090908
2014	7.194090909090908
2015	7.194090909090908
2016	7.194090909090908
2017	7.239545454545453
2018	7.239545454545453
2019	7.239545454545453