1. You're asking the wrong person.
2. I've never given it much thought.
3. I don't think it's any of my business.
4. Your guess is as good as mine.
5. I don't have any idea what's going on.
6. It's a long story.
7. That's an interesting question.
8. It's beyond me.
9. Something like that.
10. Sort of.
11. I guess so.
12. I can't say.