Year	Number of
1980	70916
1981	65867
1982	63940
1983	62021
1984	61521
1985	58567
1986	56690
1987	56496
1988	54357
1989	53112
1990	51821
1991	50612
1992	48956
1993	48461
1994	44425
1995	43078
1996	42122
1997	42190
1998	44016
1999	40800
2000	39384
2001	35489
2002	32828
2003	31638
2004	29736
2005	27194
2006	25304
2007	24779
2008	24181
2009	23631
2010	22693
2011	22119
2012	20857
2013	20495
2014	19615
2015	18280
2016	17625
2017	16789
2018	15590
2019	14460
2020	12739