Year	Number
1971	4979
1972	6240
1973	7549
1974	6769
1975	7307
1976	5936
1977	7543
1978	9864
1979	14358
1980	22850
1981	19243
1982	23588
1983	21294
1984	22257
1985	22252
1986	24947
1987	34457
1988	29576
1989	31442
1990	33774
1991	32828
1992	31450
1993	29656
1994	26522
1995	16288
1996	22067
1997	19064
2007	3172
2011	5850
2012	6578
2013	5996
2014	8238
2015	8635
2016	6276
2017	7539
2018	9998
2019	9759
2020	8888
2021	8005