Year	Number
1999	19.23044
2000	19.05967
2001	18.94779
2002	19.06977
2003	18.43017
2004	18.45109
2005	18.0776
2006	18.16434
2007	17.41751
2008	17.29188
2009	17.08591
2010	16.82253
2011	15.08609
2012	14.78869