Iran’s currency Sunday dropped to its lowest value ever as talks to revive the country’s tattered nuclear deal with world powers remained deadlocked. Traders in Tehran exchanged the rial at 332,000 to the US dollar, up from 327,500 on Saturday. That marked more than a 4.4% change compared to June 1 when it traded at 318,000 to the dollar. Iran’s currency was trading at 32,000 rials to the dollar at the time of Tehran’s 2015 nuclear deal with world powers. The rial’s new low came as US sanctions against the country are still in force. Iran’s economy is struggling mightily mostly because of the …