Year	number
2003	11.112244897959183
2004	10.641509433962264
2005	10.52
2006	10.377952755905511
2007	10.062992125984252
2008	9.559055118110237
2009	9.09375
2010	8.921875
2011	8.534883720930232
2012	8.477272727272727
2013	8.352978723404256
2014	8.196524822695036
2015	8.057042253521129
2016	7.841197183098593
2017	7.6688732394366195
2018	7.351408450704226
2019	7.17049295774648