Year	Number
1980	4768
1981	5232
1982	4763
1983	3861
1984	3771
1985	3091
1986	3071
1987	3509
1988	3748
1989	3817
1990	4400
1991	4707
1992	7130
1993	7659
1994	9446
1995	4961
1996	6365
1997	10111
1998	10440
1999	11655
2000	12630
2001	13031
2002	12536
2003	11739
2004	12633
2005	13851
2006	14931
2007	15970
2008	15896
2009	13459
2010	13625
2011	12990
2012	14020
2013	14234
2014	14889
2015	16707
2016	16103
2017	15850
2018	14869
2019	14636
2020	13180
2021	15044