DAVID McHUGHFRANKFURT, Germany (AP) â¿¿ European Central Bank President Mario Draghi has warned that the economy of the 17 countries that use the euro remains weak and will struggle to grow even with "visibly improved" confidence among the currency union's financial markets. After the ECB's governing council left its key interest rate unchanged at the record low of 0.75 percent, Draghi insisted the bank has done its part to haul the eurozone out of its financial crisis. Markets have rallied since the ECB offered in September to buy the bonds of countries such as Spain and Italy, which are struggling with borrowing costs on their debt. Draghi said it was up to governments to improve investor confidence in the currency bloc by fixing their shaky public finances and cutting the bureaucracy and regulations that block stronger growth. "Economic activity in the euro area is expected to remain weak, although it continues to be supported by our monetary policy stance and financial market confidence has visibly improved on the back of our decisions," he said at a news conference in Frankfurt. The slack economy poses a serious risk for the eurozone because only a broad rebound will help shrink the levels of government debt that have already pushed Greece, Portugal, Ireland and Cyprus into asking for bailouts. Government debt across the eurozone now averages 90 percent of annual economic output â¿¿ well above the 60 percent limit under the region's fiscal rules. Draghi said current evidence "does not signal improvements toward the end of the year" and that growth was suffering from "heightened risk aversion," as consumers and companies seek to cut their debt and improve their finances. As part of its efforts to calm the financial crisis, the ECB in September said it was willing to buy bonds issued by heavily indebted countries with the aim of lowering their borrowing costs as long as they are willing to ask for the help and take steps to cut their deficits. Since then, stocks have risen and borrowing costs fallen â¿¿ without the ECB spending a cent to intervene. The proposal alone appears to have helped instill greater confidence in the countries' ability to pay down their debts.