Year	Number
1960	1514
1961	-7202
1962	-7261
1963	-6350
1964	-6418
1965	-7987
1966	-8919
1967	-8620
1968	-8719
1969	-8413
1970	-10433
1971	-4843
1972	-4158
1973	-2013
1974	-4044
1975	-3733
1976	-3430
1977	-2928
1978	-1675
1979	-995
1980	-33
1981	-1731
1982	-1329
1983	-2598
1984	-1331
1985	-487
1986	-608
1987	-2471
1988	-962
1989	-2873
1990	-4187
1991	3543
1992	5727
1993	6639
1994	6820
1995	6465
1996	5469
1997	5670
1998	5383
1999	5382
2000	4195
2001	21486
2002	26188
2003	25694
2004	25947
2005	24895
2006	25831
2007	27262
2008	29811
2009	31317
2010	34805
2011	16409
2012	10308
2013	-1553
2014	5009
2015	5297
2016	-300
2017	2809
2018	3193
2019	4030
2020	3621
2021	3621
2022	22011
2023	22011