Year
.
1969
3 000
---
2 465
1970
3 000
1 700
1 700
1971
3 500
3 500
2 806
1972
1 300
1 300
2 800
1973
5 000
5 000
5 341
1974
7 600
---
7 400
1975
---
13 900
12 900
1976
26 800
---
19 500
1977
28 500
---
31 225
1978
16 100
---
14 867