The combined carrying capacity of oil tankers leaving Iranian ports last month dropped 22 percent from September, vessel-tracking data compiled by Bloomberg show. The implied capacity of departing ships declined to the equivalent of 1.02 million barrels a day from 1.30 million barrels, according to signals gathered by IHS Maritime, a Coulsdon, England-based research company. The data may be incomplete because not all ship transmissions are captured. U.S. and European sanctions are curbing Iran ’s oil exports in an effort to pressure the Middle East country’s leaders to stop their nuclear program. Shipments dropped from more than 2 million barrels a day in 2011, before the latest rules took effect, according to figures from the website of the Joint Organizations Data Initiative. The table below shows estimated vessel capacities in millions of barrels a day, based on signals from tankers that stopped at Iranian ports as well as movements […]