Understanding Different type of progress % -P6

I have seen that, there are many percentage completes fields in P6. I would appreciate a lot if someone could help me in understanding the following percentages.
1. Duration % Complete
2. Duration % Complete of Original
3. Performance % Complete
4. Schedule % Complete
5. Physical % Complete

I am finding difficulty in understanding how primavera calculate all these percentages. Please help.

It would be very much helpful if the explanation is augmented with practical example.

Thanks in advance.