Year	Number
1960	545
1961	658
1962	1448
1963	1727
1964	1181
1965	1455
1966	1851
1967	2267
1968	2629
1969	2883
1970	2873
1971	2397
1972	-10502
1973	-11071
1974	-11504
1975	-11802
1976	-12042
1977	-12225
1978	-12438
1979	-12846
1980	-7390
1981	-6991
1982	-6566
1983	-6036
1984	-4894
1985	-3763
1986	-3920
1987	-5467
1988	-2573
1989	-3846
1990	-6471
1991	-6174
1992	-5662
1993	-7291
1994	-2713
1995	607
1996	421
1997	412
1998	526
1999	630
2000	613
2001	639
2002	723
2003	741
2004	-1684
2005	-1542
2006	-1410
2007	-1316
2008	-1265
2009	-1214
2010	-1145
2011	-1068
2012	-1014
2013	-978
2014	-967
2015	-976
2016	-910
2017	-948
2018	-862
2019	203
2020	-313
2021	-492
2022	-1000
2023	-1000