Year	Number
1990	25007
1991	24380
1992	23824
1993	23363
1994	22969
1995	22628
1996	22317
1997	22013
1998	23494
1999	21424
2000	21148
2001	20964
2002	20571
2003	20310
2004	20340
2005	20008
2006	19642
2007	19396
2008	19094
2009	18741
2010	26431
2011	17847
2012	17394
2013	16921
2014	16480
2015	16076
2016	15750
2017	15385
2018	15095
2019	14846
2020	14667
2021	14755
2022	14466