Year	Number
1960	51401
1961	369
1962	2383
1963	1837
1964	2787
1965	10232
1966	-6967
1967	-268
1968	-6056
1969	-5043
1970	-3856
1971	-14008
1972	-6485
1973	-3826
1974	-6487
1975	-7793
1976	-15633
1977	8791
1978	7653
1979	8024
1980	11959
1981	-14927
1982	-23807
1983	-17884
1984	-20225
1985	-13535
1986	-24426
1987	-22335
1988	-11309
1989	-2800
1990	6457
1991	-30659
1992	-20270
1993	-21956
1994	-11642
1995	-26337
1996	-24330
1997	-20429
1998	-22409
1999	-26152
2000	-1761
2001	3453
2002	6018
2003	-16908
2004	-5390
2005	-42926
2006	-34007
2007	-30331
2008	-35373
2009	-29357
2010	16843
2011	33631
2012	43451
2013	35308
2014	24940
2015	4764
2016	82589
2017	56362
2018	67934
2019	69186
2020	56880
2021	20376
2022	6425
2023	6000