Year	Number
1960	1489
1961	1594
1962	2098
1963	2098
1964	2198
1965	2303
1966	2403
1967	2495
1968	2597
1969	2700
1970	2700
1971	2700
1972	2700
1973	2700
1974	2700
1975	2700
1976	2700
1977	2700
1978	2700
1979	2495
1980	2303
1981	2098
1982	1898
1983	1898
1984	1790
1985	1696
1986	1594
1987	1489
1988	1294
1989	1189
1990	-996
1991	-9000
1992	-62997
1993	-14002
1994	-9996
1995	-1497
1996	-1998
1997	-1994
1998	492
1999	5728
2000	6069
2001	5998
2002	6015
2003	6081
2004	5595
2005	1779
2006	-958
2007	-1256
2008	-1399
2009	-1274
2010	-1190
2011	-941
2012	-725
2013	-730
2014	-870
2015	-1171
2016	-521
2017	291
2018	291
2019	291
2020	291
2021	291
2022	300
2023	300