Year	Number
1994	27.65987
1995	27.70665
1996	28.00329
1997	27.09882
1998	27.35731
1999	26.06202
2000	25.09141
2001	24.80043
2002	20.43571
2003	21.16651
2004	18.94889
2005	19.49207
2006	18.52693
2007	18.26368
2008	19.19508
2009	18.13718
2010	15.98071
2011	14.54667
2012	13.56404
2013	13.98559
2014	14.0724
2015	14.01757
2016	14.28498
2017	14.54587
2018	14.54347