It's probably cold comfort to coal miners in Australia and South Africa, but their Indonesian counterparts are bearing the brunt of the supply cuts needed to balance the market.

This is shown rather starkly by data from China and India, the world's two largest coal importers.

While the headline figure from China's 2015 coal customs data may have been the 25 percent plunge in shipments from top supplier Australia, of far greater market significance was the almost 40 percent plummet in those from Indonesia.

China imported 28.3 million tons of coal from Indonesia in 2015, giving the Southeast Asian nation a 18.1 percent share of the total of 155.8 million tons of imports, a number that excludes low-rank lignite. This was down from the 20.6 percent share it had in 2014.

In contrast, Australia's share of China's imports was 45.5 percent in 2015, up from 41.5 percent in 2014.

This means that while both major coal exporters in the Asian region were suffering from lower volumes being bought by China, Australia was able to improve its relative position against its rival by quite a significant margin.

Among China's top suppliers, Mongolia also reported gains in its market share, which rose to 9.2 percent in 2015 from 8.4 percent in 2014. North Korea's market share also jumped to 12.6 percent from 6.8 percent.

It's probably worth noting that North Korea's coal shipments to China are driven partly by politics, and this near doubling in market share may not be repeated, especially if Beijing decides to send a message to Pyongyang to be less provocative in its dealings with South Korea and the rest of the world.

Among top exporters to China, Russia also suffered a decline in market share, dropping to 10.1 percent from 11.1 percent in 2014.

The outlook for China's coal imports remains bearish, given efforts to restrict the use of the fuel for environmental reasons and excess domestic production capacity. This means that the current trend of declining imports, but with rising market share for Australia, is likely to be maintained.

Australia is still China's top supplier of coking coal, used in steelmaking, and its higher quality thermal coal will be more welcome than Indonesia's lower-grade supplies.

In past years Indonesia has held about a 60 percent share, with next biggest suppliers Australia and South Africa both under 20 percent each.