Year	number
2004	5.625
2005	5.541666666666667
2006	5.52
2007	5.52
2008	5.538461538461538
2009	5.461538461538462
2010	5.1923076923076925
2011	5.222222222222222
2012	5.185185185185185
2013	5.148148148148148
2014	5.111111111111111
2015	5.074074074074074
2016	5.074074074074074
2017	5.074074074074074
2018	5.111111111111111
2019	5.111111111111111