Year
.
1969
31 300
---
24 800
1970
44 300
41 100
39 486
1971
34 200
34 200
27 825
1972
63 900
63 900
53 362
1973
64 500
72 000
56 073
1974
22 100
---
19 760
1975
5 250
---
7 750
1976
4 900
---
5 500
1977
4 000
---
4 000
1978
9 400
---
9 400