Year	Number of
1980	13553
1981	13602
1982	13588
1983	13570
1984	12952
1985	12677
1986	12860
1987	13361
1988	14137
1989	14676
1990	16256
1991	15482
1992	18097
1993	20349
1994	21422
1995	23271
1996	24189
1997	23903
1998	25758
1999	26107
2000	27470
2001	28580
2002	29752
2003	29673
2004	28570
2005	26106
2006	24295
2007	22590
2008	21724
2009	20643
2010	18590
2011	17045
2012	16107
2013	15523
2014	14861
2015	14225
2016	12790
2017	12310
2018	11586
2019	11083
2020	7193