I dont think you understand what Im trying to calculate here?
 IM trying to figure out the hashrate where mining costs and income are in balance (for a given BTC exchange rate and for the current block reward). Thats just a number that depends on a lot of variables, but mostly electricity cost, energy efficiency, and to some extend, investment horizon, hardware production costs. There is no timeline on when we will approach this, there is no historical data to check against.