Year	Number
1960	0
1961	0
1962	0
1963	0
1964	0
1965	0
1966	0
1967	0
1968	24
1969	16
1970	30
1971	40
1972	57
1973	65
1974	72
1975	86
1976	89
1977	93
1978	-160
1979	-594
1980	-834
1981	-853
1982	-864
1983	-865
1984	-874
1985	-883
1986	-882
1987	-876
1988	-883
1989	-914
1990	-939
1991	-943
1992	-939
1993	-939
1994	-939
1995	-939
1996	-937
1997	-929
1998	-902
1999	-734
2000	-458
2001	-336
2002	-351
2003	-386
2004	-425
2005	-448
2006	-481
2007	-498
2008	-531
2009	-680
2010	-882
2011	-934
2012	-879
2013	-824
2014	-785
2015	-756
2016	-404
2017	-403
2018	-403
2019	-403
2020	-197
2021	-197
2022	0
2023	0