Year	Number
1999	25.82857
2000	26.5
2001	25.59821
2002	23.72951
2003	21.52593
2004	20.11348
2005	19.59028
2006	20.58621
2007	20.66667
2008	19.16084
2009	18.66897
2010	19.50694
2011	18.92517
2012	19.55102