In Civilization V I noticed that when you are about to finish producing a Wonder and another civilization finishes it first, you will earn gold equivalent to how much production you have produced for that Wonder.
For example, I'm constructing the Statue of Liberty (total prod of 1060 prod points) and I've finished 1000 production then another civilization completes it first. How much gold will I earn?
Is there a formula for calculating money earned from unfinished wonders?