Year	Number
1996	15.35871
1997	14.76486
1998	13.70746
1999	13.89066
2000	13.22134
2001	12.7764
2002	12.36678
2003	11.931
2005	11.85656
2006	11.45099
2007	11.2636
2008	11.12294
2009	9.72973
2010	9.42665
2011	9.15768
2012	8.74344
2013	8.41116
2014	8.0956
2015	7.76874
2016	7.55609