Year	Number
1971	806
1972	1103
1973	1553
1974	2022
1975	2727
1976	3191
1977	3876
1978	4179
1979	4474
1980	4949
1981	5424
1982	4838
1983	5290
1984	5278
1985	5691
1986	6123
1987	6793
1988	7220
1989	10785
1990	11921
1991	12526
1992	13139
1993	13940
1994	14754
1995	15449
1996	15779
1997	16148
1998	16563
1999	16889
2000	16916
2001	17573
2002	18704
2003	16323
2004	16971
2005	17255
2006	17596
2007	16523
2009	19503
2010	19401
2011	19664
2012	20019
2013	23440
2014	21644
2015	19518
2016	19073
2019	29769
2020	24646