Industrial power sales suffered their worst slump on record, plunging 19 percent in January as exporters led by automakers and steel companies closed plants and reduced output.

The drop, the fourth consecutive monthly decline, was the biggest on record, the Federation of Power Companies of Japan, which started compiling data in 1972, said in a statement Friday. Sales to steelmakers plunged the most, down 37 percent, while sales to nonferrous metal producers and machinery manufacturers dropped by 24 percent.

Sales by Tokyo Electric Power Co., Chubu Electric Power Co., Kansai Electric Power Co., Chugoku Electric Power Co. and Kyushu Electric Power Co. all dropped by record amounts. Chugoku Electric saw the biggest decline, posting a slump of 27 percent.