Because right now we have approximate return on investment of 11% monthly, therefore considering distribution over the year according to difficulty raise and estimating expansion with new equipment we came to that number as one that can be guaranteed over the year of mining. Right now we mine 0.033 BTC a day with ASICs plus 0.008 a day on Doge, total of 0.041BTC a day. We purchased equipment from reseller in January for 1150$ each 50Ghash butterfly, 700$ block erupter and scrypt rig at almost 2000$, total 7300$. Right now we mine approx. 26$ a day (at 650$ BTC) less expenses, specially electrical bill. If difficulty was not an issue we would have mined over 9000 a year (if BTC stay at or over 650$ each), but we consider it and will replace all ASICs with or without an external investment. We have plans to purchase Cointerra 2 Thash and we expect 600 Ghash Monarch from Butterfly that was pre-ordered for 2138$ plus shipping. Also we will order new GPU for scrypt mining that costs 1100$ each for 1300 Khash We have buyers who will pay 950$ for each 50Ghash Butterfly and 380$ for block erupter. So we expand our operations regardless of any investment. We cannot guarantee anything beyond 1 year of mining, because BTC difficulty is unpredictable, its price too and Scrypt coins depend on BTC heavily. But it is in our interest to make this business profitable to profit from it ourselves, otherwise it would have been pointless.