Elements - Part 1

Okay, so...
Be careful: As the numbers get higher, you'll see more Sweden.
1. England?
2. France
3. Sweden
4. France
5. France
6. [ancient]
7. Scotland?
8. England and Sweden
9. France
10. France
11. ???
12. England
13. Denmark
14. Sweden?
15. Germany
16. [ancient]
17. ???
18. Scotland?
19. England
20. England
21. Sweden
22. England
23. Mexico
24. France
25. Sweden