Year	Number
1971	758
1972	1067
1973	1089
1974	1359
1975	1554
1976	1398
1977	1637
1978	2240
1979	2551
1980	3144
1981	3812
1982	4076
1983	4429
1984	4791
1985	4978
1986	5057
1987	5537
1988	5799
1989	6536
1990	7094
1991	7742
1992	8130
1993	8083
1994	8755
1995	9577
1996	10008
1997	11367
1999	13304
2000	14570
2001	17528
2002	19069
2004	24213
2005	27821
2006	28534
2007	32864
2008	38947
2009	42532
2011	49099
2012	52793
2013	54817
2014	55825
2015	55085
2016	55405
2017	57182
2018	60125
2019	60822