Year	Number
1971	915
1972	1041
1973	1104
1978	3085
1979	3679
1980	3705
1981	4703
1984	8419
1985	8141
1986	10146
1988	11173
1990	11720
1992	10198
1993	12838
1994	12713
1995	11635
1996	11269
1998	11437
1999	11802
2000	12402
2001	12686
2002	13296
2003	13771
2004	14257
2005	15891
2006	15987
2007	17110
2008	18117
2009	18598
2010	21498
2011	24652
2012	27686
2013	31011
2014	32757
2015	34200
2016	36260
2017	37360
2019	38576
2020	37752
2021	36771
2022	35584