april 1981

april 1981: 145 companies

2. april 1981 16 companies

3. april 1981 4 companies

4. april 1981 4 companies

6. april 1981 12 companies

7. april 1981 8 companies

8. april 1981 5 companies

9. april 1981 4 companies

10. april 1981 5 companies

11. april 1981 6 companies

13. april 1981 6 companies

14. april 1981 12 companies

15. april 1981 4 companies

16. april 1981 6 companies

17. april 1981 5 companies

18. april 1981 1 companies

20. april 1981 7 companies

21. april 1981 6 companies

22. april 1981 8 companies

23. april 1981 7 companies

28. april 1981 7 companies

29. april 1981 8 companies

30. april 1981 4 companies