Year	Number
1960	58160
1961	56670
1962	54960
1963	53163
1964	51283
1965	49223
1966	47100
1967	45127
1968	43254
1969	41481
1970	40108
1971	39089
1972	38043
1973	37061
1974	36234
1975	35802
1976	35525
1977	35385
1978	35566
1979	35854
1980	36271
1981	36610
1982	37553
1983	38324
1984	38476
1985	39174
1986	39689
1987	39718
1988	39795
1989	39908
1990	39883
1991	40472
1992	40438
1993	40331
1994	40041
1995	39543
1996	39097
1997	38696
1998	38177
1999	37631
2000	37107
2001	36508
2002	35730
2003	34855
2004	33957
2005	33087
2006	32233
2007	31422
2008	30794
2009	30378
2010	29964
2011	29540
2012	29267
2013	29142
2014	29238
2015	29525
2016	29937
2017	30584
2018	31394
2019	32315
2020	32758
2021	32784
2022	33624
2023	35187