Year	Number of
1980	4057
1981	4051
1982	4577
1983	3881
1984	5694
1985	4759
1986	5233
1987	5848
1988	6002
1989	6822
1990	9132
1991	11710
1992	16237
1993	20125
1994	23959
1995	30831
1996	35735
1997	43762
1998	47077
1999	50138
2000	50855
2001	56222
2002	59170
2003	57117
2004	56162
2005	50454
2006	44328
2007	40277
2008	36650
2009	42971
2010	44209
2011	38404
2012	35760
2013	32899
2014	29653
2015	26990
2016	26618
2017	25848
2018	25204
2019	21008
2020	15728