Year	Number
1999	32.11793
2000	32.63689
2002	35.02217
2004	26.73758
2005	25.84798
2006	25.40764
2007	24.38838
2008	24.03361
2009	22.3763
2010	23.2969
2011	21.88763
2012	20.99601
2013	20.99118
2014	19.89163
2015	19.20793
2017	18.31513