The base reward is 10% but that can be increased by refereals.
How much does each referral increase the reward?
(I know it depends on the amount you deposited and the amount your referral deposits, I'm hoping you can clarify those factors.)
Ex: I deposit 10BTC and I refer someone who deposits 10BTC. Would my reward now be 11% or 20%?
http://www.links-pyramining.com/mastering-pyraminingHere you can also find an investment calculator.