12.5 BTC is correct. But there is almost no chance to solve a block while solo mining.
Mining in a pool give you constant payout. But it´s pretty low.
I am making 35 GH/s with one stick. The actual Hashrate inside the network is about 35 EH/s. That´s 35 000 000 000 GH/s. So, if I´m correct here, there is a chance of about 0,000 000 1 % to hit a block with a well running 2Pac.