Power usage in Japan dropped last year to the lowest level since 1998 as households and businesses conserved electricity amid a stagnant economy and shrinking population.

The country consumed 806.03 terawatt-hours of electricity from Japan's 10 regional power utilities, down 2.7 percent from 2014, according to data released Friday by the Federation of Electric Power Companies of Japan.

The drop in demand by the world's third-biggest economy highlights the difficulties facing the nation's utilities. The total revenue of the country's top three power generators will probably fall 5.5 percent this fiscal year, according to data compiled by Bloomberg. The nation's declining population, along with the government's efforts to boost electricity efficiency, will continue to pressure balance sheets.