Year	Number
1994	14.16302
1995	13.91786
1996	14.11091
1997	14.72698
1998	15.0985
1999	15.10056
2000	15.96573
2001	17.6768
2002	17.52131
2003	16.03691
2004	16.5316
2005	16.82452
2006	16.95289
2007	15.8548
2008	15.70747
2009	15.78317
2010	15.69338
2011	16.25504
2012	16.14555
2013	17.50838
2014	16.98343
2015	16.19672
2016	15.60624
2017	15.38001
2018	15.31109