Industrial power demand rose 9.1 percent, on-year to year, 21.0 billion kilowatt-hours last month, with growth numbers moving up from a gain of 8.5 percent tallied in May, according to the report. Industrial power sales serve as a barometer of industrial activity because companies use more electricity during times when business is good and cut back to cope with falls in orders. Demand from machinery and equipment manufacturers shot up 18.1 percent on-year, with sales to local oil refineries and carmakers gaining 14.9 percent and 12.3 percent, respectively. Demand from shipyards and steelmakers rose 11.5 percent and 11.0 percent each last month with electricity sales to semiconductor manufacturers gaining 9.7 percent. Industrial power sales cover both the manufacturing and mining businesses, accounting for 59 percent of all domestic electricity sales supplied last month by the state-run Korea Electric Power Corp. Overall sales of electricity, meanwhile, reached 35.8 billion kilowatt-hours last month, up 5.7 percent from a year earlier, marking the 27th consecutive month of increases. The growth rate compares with a 4.9 percent expansion reported in the previous month. Total power sales include electricity used by educational institutions, homes, shops, farms and for public use, such as for streetlights, the ministry said.