Year	Number
1999	13.91369
2000	13.51701
2001	13.17893
2002	12.66532
2003	12.15654
2004	11.53643
2005	11.11846
2006	10.87657
2007	10.61162
2008	10.28639
2009	10.10561
2010	9.866
2011	9.59987
2012	9.49576
2013	9.31016
2014	8.99388
2015	8.55966
2016	8.3172
2017	8.21593
2018	8.11808