Year	Number
1970	2449
1971	2516
1972	2659
1973	2596
1974	2967
1975	3218
1976	3557
1977	3714
1978	3985
1979	4038
1980	3837
1981	3843
1982	3989
1983	4453
1984	4886
1985	5267
1986	5917
1987	6678
1988	7649
1989	7863
1990	7944
1991	9904
1992	10251
1993	10735
1994	11956
1995	12198
1996	12751
1997	12496
2014	82810
2016	113409
2017	112223
2018	102982
2019	105802
2020	106006