SOFIA (Bulgaria), June 21 (SeeNews) -Â Bulgarian machine engineering company Hydraulic Elements and Systems (HES) [BUL:4HE] said on Friday that its sales revenue grew by 9.40% to 29.68 million levs ($17.2 million/15.2 million euro) in January-May, and that it expects an 8.55% rise in its first-half sales revenue, to 35.08 million levs.