Why is copyright 70 years?

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Tags

1. #computed
2. #years
3. #copyright
4. #duration
5. #authorship
6. #works
7. #protection
8. #these
9. #statutory
10. #after
11. #category
12. #generally
13. #nature
14. #created
15. #guaranteed
16. #january
17. #however
18. #depending
19. #least