The US boom reflects continuing worldwide growth for energy drinks, as an increasing number of manufacturers look to tap into consumer demands for functional and health benefits in drinks. Zenith International's research director, Gary Roethenbaugh said the US was becoming an increasingly significant market for energy drinks, and as such was driving global growth for the product. "If the level of activity and product development in the US continues, it could represent 45 percent of worldwide volume in five years," stated Roethenbaugh. "We also expect to see double digit growth in East Europe and the Middle East, with Latin America, Australasia and West Europe making good gains too." Austria, Ireland, New Zealand, Slovenia and Kuwait were picked as significant individual markets for future growth, according to Zenith The rapid levels of consumption growth within the US were attributed primarily to sales of the top five brands - Red Bull, Monster, Rockstar, Full Throttle and SoBe No Fear - in the market, though innovation remains vital to the industry, Zenith added. "Although US growth has been dominated by male-oriented energy drinks, manufacturers there are successfully tapping in to a wider trend towards healthier products and consumers are enjoying a new wave of all natural energy," stated Roethenbaugh. "They are also extending their brands to appeal to a wider range of consumers." These developments are expected to lead to strong per capita consumption growth in the coming years, Zenith said. While the current average consumption per person of energy drinks in the US market of three liters remains significantly behind leader Thailand, which boasted 11.5 liters per person this year, sharp increases are expected, Zenith said. The US consumption rate is therefore expected to more than double by 2011 to eight liters per person, the analyst added. In terms of regional market share, despite the US market's prominance, Asia-Pacific continued to dominate demand last year accounting for 47.8 percent of all energy drink consumption, Zenith said. North America was the second most important market place with a 29.1 percent global share followed by Western Europe with 12.5 percent. Emerging markets for energy drinks link Eastern Europe and Latin America accounted for 2.8 percent and 3.7 percent respectively.