The average liabilities held by South Korea's heavy debtors edged up on-year in 2013, data showed Sunday, casting further clouds over the country's economy amid mounting household debts. South Koreans who have borrowed money from more than three financial firms saw their average debt reach 96.2 million at end-2013, gradually expanding every year since the 88.3 million won posted in 2010, the data compiled by the Bank of Korea (BOK) showed.