Year	Number
1994	14.83182
1995	15.3902
1996	15.66646
1997	15.84125
1998	15.35157
1999	16.13001
2000	16.4498
2001	16.75766
2002	16.79296
2003	17.04551
2004	16.76781
2005	16.44861
2006	15.98068
2007	15.71721
2008	15.2436
2009	14.99355
2010	14.64751
2011	14.27425
2012	13.85229
2013	13.78625
2014	13.35768
2015	13.19614
2016	12.99947
2017	12.93815
2018	12.95764