By Francesco Canepa FRANKFURT(Reuters) - Greece's liabilities to the euro zone's bank payment system climbed last summer to highs not seen since 2012, as fears Greece would be forced out of the euro zone drove money out of the country, data from the European Central Bank showed on Monday. The Bank of Greece had net liabilities of 106.13 billion euros (76.77 billion pounds) towards the ECB at the end of July, according to data from the Target 2 payment system published for the first time on Monday. The Target 2 system facilitates payments between banks in different euro zone countries by channelling them through each national central bank's account at the ECB.