Year	Number
1980	2394
1981	2155
1982	1824
1983	1910
1984	1950
1985	1428
1987	1164
1988	1256
1989	1314
1990	1362
1991	1241
1992	1012
1993	1250
1994	1224
1995	1492
1996	1548
1998	2191
1999	1791
2000	1821
2001	1679
2002	1605
2003	1603
2004	1890
2005	2944
2007	4585
2010	4757
2011	4703
2012	4455
2013	4387
2014	3992
2015	3874
2016	4185
2017	4302