Exports of coal from Indonesia from January to July witnessed a steep decline by 18 percent to 186.8 million tons from a year earlier as weakening global economy has sapped demand, official said here on Tuesday.

 "The export of coal scale down significantly by 18 percent (at first seven months) compared with the same period last year. The decline is because of weakening of global demand,"said Adhi Wibowo, coal enterprises director at energy and mines ministry.

Indonesia's coal outputs from January to July also decreased by 15 percent to 232.9 tons on year, he disclosed.

As much as 46.1 million tons of the total January-July's production was sold in domestic market, said Wibowo at his office.

Indonesia is the world's largest exporter of thermal coal.