Year	Number
1971	10007
1972	9606
1973	10279
1974	10671
1975	9498
1976	11758
1977	14305
1978	13150
1979	15268
1990	16687
1992	18978
1993	20383
1999	31859
2000	35367
2001	38943
2002	42017
2003	44425
2004	46509
2005	46539
2006	46393
2007	45410
2008	41271
2009	39328
2010	38222
2011	37224
2012	35726
2013	33921
2014	32054
2015	30088
2016	28745
2017	27473
2018	26608
2019	26022
2020	26396
2021	27627
2022	28961