Year	Number
1992	14.43764
1993	14.2491
1994	14.35253
1995	14.63268
1996	14.68228
1997	14.52153
1998	14.54088
1999	14.39738
2000	14.22313
2001	14.13611
2002	13.83371
2003	13.77663
2004	13.53339
2005	13.39748
2006	13.25941
2007	13.07769
2008	12.92217
2009	12.9013
2010	12.79941
2011	12.91513
2012	13.0227
2013	13.08881
2014	12.98324
2015	12.83461
2016	12.66582
2017	12.70184
2018	12.69984