By Helen Murphy and Luis Jaime Acosta Reuters May 28, 2012 BOGOTA - Colombia, one of the world's top coffee exporters, could more than double production by the end of the decade if its drive to tap new markets such as Russia and China prove successful, said the head of the coffee federation. The world's top producer of high quality arabica beans aims to churn out a record 18 million bags for export by 2020 as it increases crop area and recovers output levels curbed by bad weather, fungus and a tree renovation program, federation chief Luis Genaro Munoz told Reuters. Coffee output slumped last year to a three decade low of 7.8 million 60-kilogram (132-pound) sacks. The last time Colombia produced close to Munoz's goal was in 1992 when it reached above 16 million sacks. Munoz, who expects production next year to hit 9 million sacks, is betting that young, affluent Chinese and Russian consumers will develop a taste for Colombian coffee, bolster...