Year	Number
1960	43621
1961	44115
1962	44714
1963	45170
1964	45529
1965	45721
1966	45693
1967	45510
1968	45167
1969	44668
1970	44027
1971	43282
1972	42456
1973	41560
1974	40605
1975	39596
1976	38561
1977	37566
1978	36684
1979	35926
1980	35236
1981	34609
1982	34099
1983	33709
1984	33409
1985	33140
1986	32827
1987	32437
1988	31975
1989	31496
1990	31032
1991	30623
1992	30317
1993	30084
1994	29892
1995	29731
1996	29576
1997	29380
1998	29143
1999	28955
2000	28755
2001	28518
2002	28351
2003	28229
2004	28072
2005	27833
2006	27555
2007	27334
2008	27273
2009	27301
2010	27224
2011	27020
2012	26755
2013	26450
2014	26108
2015	25723
2016	25317
2017	24934
2018	24592
2019	24271
2020	23967
2021	23694
2022	23407
2023	23040