SEOUL, Sept 15 (Reuters) - South Korea imported 232,723 tonnes of crude oil from Iran in August, down 85 percent from a year ago, preliminary data from Korea Customs Service showed on Saturday. That is equivalent to 1.7 million barrels, according to a Reuters calculation. The world’s fifth-largest crude buyer imported a total 12.6 million tonnes of crude last month against 13.6 million tonnes imported a year ago, the data also showed. Final data for South Korea's crude oil imports last month will be published by state-run Korea National Oil Corp (KNOC) later the month. The KNOC data is considered the industry standard for South Korea's oil imports.