Year	Number
1960	-2176
1961	-1538
1962	-1015
1963	-679
1964	-649
1965	-420
1966	-483
1967	-922
1968	-1671
1969	-2814
1970	-4120
1971	-5625
1972	-6536
1973	-6960
1974	-7085
1975	-6653
1976	-5743
1977	-3997
1978	-1469
1979	1612
1980	5588
1981	10294
1982	13490
1983	15293
1984	16236
1985	15822
1986	14071
1987	11068
1988	6641
1989	588
1990	-7183
1991	-47995
1992	-34344
1993	29470
1994	27267
1995	-52246
1996	-48626
1997	-53064
1998	-48299
1999	-48578
2000	-50791
2001	-17581
2002	-12562
2003	-8641
2004	-5673
2005	-3834
2006	-2720
2007	-2207
2008	-2613
2009	-3675
2010	-5624
2011	-8241
2012	-10440
2013	-11833
2014	-12849
2015	-13408
2016	-13569
2017	-13654
2018	-13171
2019	-12480
2020	-11592
2021	-10402
2022	-2000
2023	-2000