I did that on purpose. Options in company A are completely different than options in company B, and assuming that more is better is just silly. 3000 out of 100000 is 3%; 5000 out of 500000 is 1%. But you can't just compare percentages either, because a percentage of a more valuable company is worth more than a percentage of a less valuable company.

As an employee, you just don't know. So value them at zero. Or, if you want to be fancy, epsilon. And take the cash.