Year	Number
1995	16.08949
1996	16.75864
1997	17.21769
1999	17.08747
2000	17.56423
2001	18.57755
2002	18.57755
2003	19.5765
2006	17.04956
2007	16.40386
2008	15.83738
2009	15.45224
2010	14.90671
2011	14.47065
2012	13.84711
2013	13.42238
2014	12.61388
2015	12.4553
2016	12.30006
2017	12.26986
2018	12.32505