Year	Number
1980	1229
1981	1183
1982	1193
1983	64
1984	1302
1985	1257
1986	1407
1987	1399
1988	1396
1989	1242
1990	1225
1991	1678
1992	1834
1993	2452
1994	3084
1995	2581
1996	2507
1997	3171
1998	3740
1999	3630
2000	3770
2001	4638
2002	4168
2003	4110
2004	4453
2005	5050
2006	5464
2007	5248
2008	5492
2009	5494
2010	5952
2011	7465
2012	6977
2013	6894
2014	7888
2015	8884
2016	8795
2017	9800
2018	11506
2019	11812
2020	10748