Milan, January 21 - The Milan stock exchange's FTSE Mib index was 4% up at 18,687 points on Thursday after European Central Bank President Mario Draghi said interest rates were set to remain steady for "a long period of time". On Thursday the ECB left its main refinancing rate unchanged at a record low of 0.05%. It also left its deposit rate unchanged at -0.30%. The share price of troubled bank Monte dei Paschi di Siena (MPS) soared, taking its capital valuation above the two billion-euro threshold it had fallen below after coming under extreme pressure in recent days. The MPS share price was heading to a rise of 39.71%% but was suspended for excessive volatility.