Year	Number
1960	30196
1961	29538
1962	29456
1963	31130
1964	31375
1965	30371
1966	29871
1967	30316
1968	29260
1969	27091
1970	25585
1971	23895
1972	22811
1973	20477
1974	17410
1975	15690
1976	14102
1977	12770
1978	12129
1979	11889
1980	11698
1981	11476
1982	11169
1983	10771
1984	10466
1985	10317
1986	10381
1987	10693
1988	11166
1989	12053
1990	13410
1991	15321
1992	15238
1993	15066
1994	14844
1995	29300
1996	28461
1997	27409
1998	26473
1999	25651
2000	24617
2001	23603
2002	22352
2003	9893
2004	9454
2005	9064
2006	8725
2007	8603
2008	8389
2009	8149
2010	7470
2011	6815
2012	6467
2013	6173
2014	5928
2015	5706
2016	5537
2017	5234
2018	5043
2019	4815
2020	4600
2021	4376
2022	4632