McDonald\'s Corp. reported global same-store sales climbed 2.6 percent year on year in May despite a persistently sluggish economy, local media reported Monday. The Chicago Tribune said McDonald\'s May sales increased 2.6 percent. The Oak Brook-based burger giant reported gains in all regions of the world, including a 2.4 percent gain in the U.S., a 2 percent gain in Europe and a 0.9 percent increase in the Asia- Pacific, Middle East and African regions. McDonald\'s has struggled to post gains throughout the world since posting its first monthly sales decline in nearly a decade in October 2012. The chain has cited increased competition in the U.S., austerity measures in Europe, and declines in eating out around the world. In many places, however, the world\'s largest chain of hamburg fast food restaurants has said that it continues to gain market share. \"McDonald\'s strategic initiatives and diligent focus on the customer generated global comparable sales growth in May amidst ongoing uncertainty in the macro environment,\" CEO Don Thompson said in a statement. McDonald\'s reported improvements in sales in most areas in Asia- Pacific, Middle East and Africa, except flat performance in Japan, and declines in China. The fast food chain runs over 34,000 restaurants around the world.