Year	Number
1960	12174
1961	21080
1962	23312
1963	22134
1964	21439
1965	28207
1966	7449
1967	14132
1968	4930
1969	1669
1970	7960
1971	-35585
1972	-13077
1973	-699
1974	44211
1975	75448
1976	72700
1977	129022
1978	111237
1979	137656
1980	184467
1981	90174
1982	73253
1983	-507539
1984	67234
1985	19791
1986	12447
1987	40048
1988	72254
1989	81688
1990	107212
1991	12661
1992	63692
1993	60446
1994	98121
1995	43504
1996	54743
1997	67109
1998	62195
1999	41275
2000	34146
2001	37267
2002	39619
2003	4194
2004	16528
2005	-46749
2006	-41526
2007	-38960
2008	-43402
2009	-48397
2010	18073
2011	38226
2012	41741
2013	10588
2014	-49351
2015	-145917
2016	-54315
2017	15016
2018	-81384
2019	-103989
2020	-4824
2021	-76364
2022	-59996
2023	-59996