Year	Number
1960	5730
1961	5530
1962	5387
1963	5358
1964	5400
1965	5492
1966	5568
1967	5620
1968	5629
1969	5616
1970	5557
1971	5432
1972	5220
1973	4798
1974	3730
1975	2247
1976	689
1977	-570
1978	-1441
1979	-2761
1980	-4609
1981	-4410
1982	-3861
1983	-5037
1984	-5705
1985	-6209
1986	-6397
1987	-7319
1988	-8791
1989	-3927
1990	798
1991	5400
1992	8347
1993	8183
1994	4802
1995	-462
1996	-25893
1997	-16799
1998	-9721
1999	-9212
2000	-9473
2001	-9062
2002	-8595
2003	-15713
2004	-9254
2005	-8252
2006	-9619
2007	-9637
2008	-9605
2009	-9615
2010	-9627
2011	-9636
2012	-9598
2013	-9603
2014	-9609
2015	-9612
2016	-9616
2017	-9616
2018	-9614
2019	-9612
2020	-4502
2021	-4503
2022	-4000
2023	-4000