Year	Number
1960	34588
1961	34368
1962	34110
1963	33824
1964	33533
1965	33227
1966	32905
1967	32553
1968	32123
1969	31557
1970	30870
1971	30360
1972	30053
1973	29760
1974	29419
1975	29059
1976	28616
1977	28111
1978	27620
1979	27190
1980	26783
1981	26461
1982	26192
1983	25921
1984	25582
1985	25179
1986	24765
1987	24446
1988	24240
1989	23960
1990	23571
1991	23377
1992	23203
1993	22978
1994	22718
1995	22387
1996	22059
1997	21799
1998	21592
1999	21450
2000	21369
2001	21281
2002	21098
2003	20877
2004	20696
2005	20662
2006	20782
2007	20943
2008	20965
2009	20667
2010	20437
2011	20458
2012	20526
2013	20614
2014	20733
2015	20841
2016	21015
2017	21384
2018	21823
2019	22157
2020	22362
2021	22560
2022	22951
2023	23451