Year	Number
1960	24465
1961	24762
1962	24934
1963	24974
1964	24884
1965	24702
1966	24508
1967	24220
1968	23765
1969	23299
1970	22872
1971	22389
1972	21849
1973	21260
1974	20578
1975	19833
1976	19178
1977	18555
1978	17942
1979	17387
1980	16861
1981	16339
1982	15845
1983	15452
1984	15073
1985	14621
1986	14181
1987	13804
1988	13475
1989	13197
1990	12851
1991	12429
1992	11970
1993	11499
1994	11008
1995	10486
1996	9968
1997	9457
1998	8972
1999	8619
2000	8403
2001	8186
2002	7970
2003	7800
2004	7648
2005	7504
2006	7349
2007	7255
2008	7291
2009	7394
2010	7467
2011	7498
2012	7502
2013	7506
2014	7503
2015	7505
2016	7488
2017	7457
2018	7399
2019	7266
2020	7055
2021	6836
2022	6621