Year	Number
1993	14.01173
1994	14.59612
1995	14.52909
1996	14.87898
1997	14.86628
1998	15.12233
1999	15.10373
2000	13.65752
2001	13.52357
2002	13.66035
2003	13.47423
2004	13.13703
2005	12.96378
2006	12.76316
2007	12.45657
2008	12.18647
2009	12.18134
2010	11.98917
2011	11.91519
2012	11.82716
2013	11.75844
2014	11.26402
2015	11.04344
2016	10.9573
2017	11.08688