Year	Number
1960	0
1961	0
1962	0
1963	0
1964	0
1965	0
1966	0
1967	0
1968	0
1969	0
1970	0
1971	0
1972	0
1973	0
1974	0
1975	0
1976	0
1977	0
1978	0
1979	0
1980	0
1981	0
1982	0
1983	0
1984	0
1985	0
1986	0
1987	0
1988	0
1989	0
1990	0
1991	0
1992	0
1993	0
1994	-525
1995	-3093
1996	-3507
1997	-3738
1998	-3706
1999	-3436
2000	-3139
2001	-2883
2002	-2770
2003	-2720
2004	-2759
2005	-2860
2006	-2950
2007	-3020
2008	-3046
2009	-3055
2010	-3047
2011	-2958
2012	-2918
2013	-2936
2014	-3039
2015	-3200
2016	-3218
2017	-3222
2018	-3223
2019	-3139
2020	-1589
2021	-1589
2022	-2000
2023	-2000