Year	Number of
1980	27749
1981	27373
1982	25520
1983	23846
1984	22255
1985	22201
1986	22768
1987	22517
1988	22436
1989	23495
1990	25701
1991	26283
1992	26673
1993	25107
1994	24205
1995	22728
1996	21210
1997	19751
1998	18287
1999	17501
2000	16310
2001	15945
2002	15056
2003	14838
2004	14502
2005	14080
2006	13779
2007	13299
2008	12904
2009	11545
2010	11181
2011	10521
2012	9945
2013	9115
2014	8949
2015	9058
2016	8814
2017	8662
2018	8561
2019	8493
2020	6849