Year	Number
1960	-1872
1961	-1990
1962	-2117
1963	-2371
1964	-2302
1965	-2518
1966	-4910
1967	-6723
1968	-7128
1969	-6985
1970	-8066
1971	-9326
1972	-9526
1973	-9927
1974	-9995
1975	-10121
1976	-9158
1977	-9579
1978	-9281
1979	-8773
1980	-9025
1981	-8943
1982	-10153
1983	-9934
1984	-10213
1985	-10556
1986	-12832
1987	-14990
1988	-18063
1989	-19356
1990	-20264
1991	-26036
1992	-22974
1993	-23215
1994	-24300
1995	-25582
1996	-20062
1997	-17064
1998	-16496
1999	-17431
2000	-18142
2001	-19091
2002	-19709
2003	-20304
2004	-20731
2005	-21268
2006	-21425
2007	-22604
2008	-24176
2009	-24601
2010	-23419
2011	-23954
2012	-24048
2013	-23818
2014	-23690
2015	-23389
2016	-22404
2017	-22717
2018	-22554
2019	-22269
2020	-11924
2021	-11748
2022	-8677
2023	-8409