Year	Number
1971	5086
1972	5305
1973	5570
1974	5498
1975	5866
1976	6213
1977	6530
1978	6540
1979	6877
1980	7054
1981	6862
1982	7278
1983	7932
1984	8356
1985	8442
1986	8593
1987	8560
1988	8124
1989	8440
1990	8405
1991	8156
1992	7963
1993	8688
1994	8363
1995	8274
1996	8718
1997	9677
1998	10853
1999	15447
2000	15567
2001	17788
2002	21756
2003	22577
2004	26737
2005	27688
2006	30515
2007	33230
2008	35442
2009	38413
2010	40052
2011	43629
2012	50676
2013	50095
2014	51363
2015	52148
2016	60288
2017	66418
2018	65485
2020	63784
2021	68691