Year	Number
1960	1268
1961	1089
1962	818
1963	725
1964	498
1965	-421
1966	-727
1967	-836
1968	-893
1969	-917
1970	-1060
1971	4147
1972	6147
1973	6382
1974	6647
1975	6833
1976	6930
1977	6948
1978	6913
1979	6798
1980	6613
1981	4206
1982	3553
1983	3811
1984	4108
1985	4256
1986	4457
1987	4713
1988	4871
1989	4638
1990	4605
1991	6605
1992	6728
1993	6967
1994	7424
1995	7706
1996	7844
1997	7730
1998	7388
1999	6737
2000	6264
2001	5704
2002	4197
2003	28186
2004	53424
2005	53401
2006	53765
2007	54165
2008	53870
2009	52049
2010	-17076
2011	-20040
2012	11754
2013	27227
2014	36320
2015	29250
2016	29052
2017	29024
2018	-3601
2019	-17127
2020	-48716
2021	-9150
2022	0
2023	0