BUENOS AIRES, May 20 (Reuters) - Argentina's black-market peso fell around 2 percent to 11.53 per U.S. dollar on Tuesday as worries over a gradual devaluation of the official exchange rate for the currency grew, foreign exchange traders said.
The so-called blue rate, as measured by Reuters, has dipped since the official peso rate started depreciating last week. After holding steady at around 8.0 since a devaluation of around 20 percent in January, the official peso is trading at 8.06 against the dollar.
Argentina's central bank controls the official rate, dipping into dwindling reserves to keep the peso steady, and to avoid fueling one of the world's highest inflation rates. (Reporting by Jorge Otaola; Writing by Sarah Marsh; Editing by Peter Galloway)