Year	Number of
1980	16406
1981	16693
1982	17292
1983	17305
1984	16359
1985	15987
1986	14681
1987	13368
1988	13267
1989	12636
1990	12309
1991	12185
1992	12606
1993	13887
1994	13683
1995	13450
1996	13397
1997	12621
1998	12276
1999	11871
2000	11767
2001	11456
2002	11548
2003	10844
2004	11413
2005	10576
2006	9675
2007	10227
2008	9196
2009	7701
2010	7336
2011	9733
2012	8758
2013	8933
2014	9195
2015	9601
2016	10347
2017	10170
2018	10320
2019	11446
2020	9322