SOFIA (Bulgaria), December 19 (SeeNews) -Â Bulgarian machine engineering company Hydraulic Elements and Systems (HES) [BUL:4HE] said on Wednesday that it expects its sales revenue to rise by an annual 12.1% to 61.8 million levs ($36.0 million/31.6 million euro) in 2018, followed by a 3.8% year-on-year decrease in 2019.