Year	Number
1994	16.58897
1995	16.56094
1996	15.69885
1997	15.55716
1998	15.86353
1999	16.17653
2000	16.32508
2001	16.39225
2002	16.49106
2003	16.81774
2004	17.53799
2005	16.96849
2006	16.0725
2007	14.94714
2008	14.15707
2009	13.60338
2010	13.62899
2011	13.66072
2012	13.42862
2013	13.14394
2014	13.22319
2015	12.93252
2016	12.6058
2017	12.94795
2018	12.95023