Year	Number of
1980	4758
1981	5033
1982	4411
1983	4707
1984	4404
1985	5335
1986	6260
1987	7581
1988	8359
1989	9431
1990	12395
1991	14743
1992	14237
1993	17105
1994	19496
1995	19155
1996	20630
1997	20676
1998	22674
1999	24396
2000	23604
2001	26094
2002	24595
2003	28234
2004	27030
2005	25491
2006	25054
2007	24461
2008	23929
2009	22674
2010	21092
2011	19361
2012	20335
2013	17779
2014	16267
2015	15737
2016	15516
2017	16512
2018	15632
2019	16902
2020	15133