Year	Number
1972	19353
1973	18552
1974	17984
1975	17711
1976	17404
1977	17029
1978	16799
1979	16749
1980	16468
1981	16117
1982	16135
1983	16176
1984	15549
1985	14728
1986	14112
1987	13500
1988	12827
1989	11946
1990	11118
1991	10812
1992	10662
1993	10334
1994	9853
1995	9069
1996	8339
1997	7819
1998	7254
1999	6601
2000	6069
2001	5710
2002	5505
2003	5462
2004	5443
2005	5343
2006	5337
2007	5388
2008	5444
2009	5415
2010	5109
2011	4823
2012	4679
2013	4468
2014	4192
2015	3950
2016	3688
2017	3341
2018	2986
2019	2684
2020	2471
2021	2372
2022	2323