Quadrillion now, but costs will drive down and once is turned to gold, it stays gold. In the far future where all gold was mined this will be the only process left to get more. Or explode stars and capture gold from them.

I joke with my Son all the time about turning Mercury into gold (He works in the nuclear industry).

Once you get past the enormous energy costs to do this you have a secondary problem, all the gold produced this way is radioactive and it beta decays to.. Mercury.