Burundi’s coffee revenues fell 7 per cent in September from the previous month due to lower sales on slacker global demand, the nation’s industry regulator said on Tuesday.The tiny central African country collected US$5.5 million from the sale of 1,543,380 kg, down from US$5.9 million earned in August from the export of 1,617,960 kg."In September, the international market was uncertain and this pushed buyers to be reluctant. This is the reason behind that drop in terms of earnings,” said regulator ARFIC in its monthly report.Weak demand drove down mild arabica coffee differentials to multi-year lows and is expected to hit the premium paid for arabica beans over the coming months.ARFIC estimates earnings for the 2012/13 season at US$61.4 million, somehow closer to the US$61.2 million collected in the 2011/12 crop. The expected high supply globally should lower prices on world markets, says Burundi’s coffee regulator.Coffee is the country’s top hard currency earner and supports some 800,000 smallholder farmers in a nation of 8 million people.