Year	Number
1994	15.30449
1995	15.88508
1996	16.13382
1997	16.14989
1998	15.71615
1999	16.48595
2000	16.70109
2001	17.07265
2002	17.02255
2003	17.20455
2004	16.98217
2005	16.72377
2006	16.32934
2007	16.12375
2008	15.76591
2009	15.5497
2010	15.16858
2011	15.04711
2012	14.72741
2013	14.69578
2014	14.29548
2015	14.18144
2016	14.03769
2017	13.9181
2018	13.925