Bulgarian public gas supplier Bulgargaz said that it has proposed a 13.89% increase in the wholesale price of natural gas, to be valid in the fourth quarter of 2018.According to the proposal, the price will rise by 55.7 levs to 456.65 levs ($271.4/233.5 euro) per 1,000 cubic metres, excluding VAT and excise duty, Bulgargaz said in a statement on Monday.Bulgarian energy regulations require Bulgargaz to set the gas price quarterly, taking into account global oil prices and the lev/dollar exchange rate.The Energy and Water Regulatory Commission (EWRC) has the final say on proposed changes in the wholesale price, at which the state-owned company sells natural gas to end-suppliers and customers directly connected to its transmission network.Bulgaria imports almost all the natural gas it needs from Russia via a pipeline crossing Ukraine, Moldova and Romania.(1 euro = 1.95583 levs)