EBITA also fell 11% while pre-tax profits plummeted 18%.
The group's poor performance was due to the weakness of a number of key trading currencies against the dollar, it said.
The underlying organic sales and volume figures reveal solid growth.
The group posted organic global revenue growth of 4%, driven in part by premium lager sales, which were up 7%.
The second quarter was stronger than the first, showing organic sales and volume growth of 6% and 2% respectively.
Performance across the developing world was strong, with organic revenue growth in Latin America, Africa and Asia-Pacific up 8%, 9% and 4% respectively.
The investor dividend is up 9% to $0.2825 per share.
Alan Clark, chief executive of SABMiller, said: "We had a good first half, stripping out the effects of adverse exchange rates, with strong growth in Africa and Latin America and better mix across all of our regions.
“On an organic, constant currency basis, group earnings and margins improved as a result of growing volumes and NPR per hectolitre, and continued cost savings.
"In our African and Latin American markets, our affordability strategies are helping us to grow beer’s share of total alcohol.
“At the other end of the price ladder, our volume growth in premium lagers included particularly strong growth of our global premium brands.
“Our reported results were again negatively impacted by the depreciation of major operating currencies against the US dollar.”
The UK was a bright spot for the group in Europe, with half-year organic revenue up 4.4%, on the back of strong sales for its premium imported beers.
Peroni Nastro Azzurro remains the UK’s most popular world beer, and Czech brands Pilsner Urquell and Kozel both saw strong double-digit growth year on year.
Gary Haigh, managing director of Miller Brands UK, said: “Peroni, Pilsner Urquell and Kozel are certainly capturing the imagination of consumers and their thirst and enthusiasm for genuinely imported super-premium beers.
“We continue to seek ways to innovate and remain committed to exciting both our consumers and industry partners about these exceptional beers.”
Connor Campbell, senior market analyst at www.spreadex.com, said: “In all honesty, the contents of SABMiller’s half-year report was always going to have a limited impact given that the beer-giant agreed terms for its £71 billion tie-up with AB InBev only yesterday.
“However, there is still some way to go before that takeover is completed, meaning investors would do well to keep an eye on SAB’s figures.
“Adverse currency headwinds dragged the company’s revenue from 4% growth to a 9% decline, whilst pre-tax profit plunged by a worrying 18%.
“To combat this SAB raised its dividend by 9%, in a fairly transparent move to draw attention away from its less-than-flattering numbers.”
Final details of the SABMiller's £71 billion takeover by AB InBev were made public yesterday.
The group is on track to deliver over £282 million of annual savings by the end of the financial year, ahead of its target of £329 million by March 31, 2018.
It expects to cut another £361 million of costs out of the business by 2020.
AB InBev expects to achieve some £920 million of additional annual savings when it assumes control of the business.