Year	Number
1960	23238
1961	23373
1962	23549
1963	23677
1964	23772
1965	23810
1966	23768
1967	23654
1968	23460
1969	23170
1970	22860
1971	22639
1972	22441
1973	22172
1974	21833
1975	21442
1976	20973
1977	20438
1978	19823
1979	19157
1980	22026
1981	17680
1982	16776
1983	15784
1984	14851
1985	13925
1986	13054
1987	12385
1988	11829
1989	11235
1990	10647
1991	10085
1992	9539
1993	8987
1994	8460
1995	7937
1996	7406
1997	6882
1998	6437
1999	6010
2000	5537
2001	5044
2002	4546
2003	4092
2004	3688
2005	3337
2006	3054
2007	2808
2008	2603
2009	2437
2010	2298
2011	2180
2012	2066
2013	1962
2014	1874
2015	1782
2016	1666
2017	1552
2018	1454
2019	1379
2020	1315
2021	1255
2022	1200