Year	Number
1970	20498
1972	16939
1973	14869
1975	16383
1976	13170
1978	15386
1979	18653
1980	19807
1981	20568
1982	24430
1985	27519
1986	26545
1987	26901
1989	28880
1990	31089
1991	32014
2012	4282
2013	8051
2014	12447
2015	13670
2016	13386
2017	16264
2018	8795
2019	6932
2020	9246
2021	10929
2022	10882