Walgreen raises dividend 28.6 percent Mon Apr 9, 2012 7:09pm EDT (Reuters) - Walgreen Co (WAG.N), which operates the largest U.S. drugstore chain, raised its dividend on Monday. Walgreen, with a fleet of about 7,850 stores, will now pay a quarterly dividend of 22.5 cents per share, up 28.6 percent increase over the year ago dividend. Reporting By Phil Wahba, editing by M.D. Golan