Year	Number
1971	69160
1972	66027
1973	64186
1974	63446
1975	56649
1976	56602
1977	55366
1978	55166
1979	54309
1980	50579
1981	48701
1982	46095
1983	46198
1984	46653
1985	47381
1986	50990
1987	54254
1988	56530
1989	58720
1990	60841
1991	62962
1992	63454
1993	64313
1994	64907
1995	64884
1996	64660
1997	64761
1999	64248
2000	63952
2001	63637
2002	63717
2003	62868
2004	61731
2005	61247
2006	59710
2007	57785
2008	56799
2009	55837
2010	54806
2011	54371
2012	54272
2013	54069
2014	53129
2015	53773
2016	54541
2017	55862
2018	57079
2019	58473
2020	59195
2021	58543