Year	Number
1960	22033
1961	48159
1962	52533
1963	57007
1964	61514
1965	65581
1966	69540
1967	74030
1968	77914
1969	65595
1970	37326
1971	24030
1972	26751
1973	30093
1974	33604
1975	37609
1976	42099
1977	45625
1978	27782
1979	-10866
1980	-30940
1981	-30943
1982	-29711
1983	-27776
1984	-24724
1985	-19965
1986	-13291
1987	-6265
1988	-470
1989	-41670
1990	-73485
1991	-29065
1992	-33270
1993	-37383
1994	-41799
1995	-45888
1996	-50325
1997	-48369
1998	-49882
1999	-61969
2000	-66569
2001	-48649
2002	-47697
2003	-44098
2004	-38839
2005	-33395
2006	-29201
2007	-27023
2008	-24037
2009	-20379
2010	-20381
2011	-20380
2012	-20382
2013	-20380
2014	-20382
2015	-20380
2016	-35209
2017	-48561
2018	-60066
2019	-69397
2020	-39203
2021	-39201
2022	-19999
2023	-19999