Year	Number
1960	8812
1961	11972
1962	13540
1963	14345
1964	15600
1965	18850
1966	15447
1967	18468
1968	17297
1969	17491
1970	17995
1971	6315
1972	10730
1973	-55665
1974	-53905
1975	-52795
1976	-60596
1977	-37899
1978	-36071
1979	-44199
1980	-37697
1981	-52859
1982	-79901
1983	18430
1984	11430
1985	6076
1986	-7352
1987	-11643
1988	-13044
1989	-26579
1990	-40864
1991	-79081
1992	-80697
1993	-83251
1994	-71386
1995	-75127
1996	-65800
1997	-58984
1998	-62299
1999	-81905
2000	-106816
2001	-131190
2002	-150317
2003	-165833
2004	-169843
2005	-185133
2006	-186225
2007	-185117
2008	-180646
2009	-158651
2010	-116543
2011	-82753
2012	-61554
2013	-62882
2014	-74923
2015	-94128
2016	-87935
2017	-105438
2018	-114634
2019	-100810
2020	-66228
2021	-35382
2022	-34998
2023	-34998