Year	Number
1992	33.6874838041
1993	32.4397512309
1994	31.1894273128
1995	29.9391033947
1996	28.6887794765
1997	27.4384555584
1998	26.1881316403
1999	24.9378077222
2000	23.6848924592
2001	22.858512568
2002	22.029541332
2003	21.2005700959
2004	20.3715988598
2005	19.5387406064
2006	19.4812127494
2007	19.4195387406
2008	19.3583830008
2009	19.2969681265
2010	19.240735942
2011	17.9609354755
2012	16.6811350091
2013	15.4013345426
2014	14.1215340762
2015	11.8022803835
2016	12.0821456336
2017	13.8701736201
2018	13.8701736201
2019	13.7289453226
2020	12.2557657424