Year	Number
2001	16.55161
2002	15.55628
2005	16.52497
2006	15.66345
2007	15.40229
2008	14.55433
2009	14.95751
2010	14.64105
2011	14.80473
2012	14.81298
2013	14.70939
2014	14.20757
2015	13.86122
2016	12.50078
2017	13.42011
2018	14.21859