China Online Education Group ( NYSE:COE – Get Rating ) was the recipient of a large decline in short interest in May. As of May 15th, there was short interest totalling 323,900 shares, a decline of 17.2% from the April 30th total of 391,400 shares. Based on an average daily trading volume, of 151,500 shares, the short-interest ratio is currently 2.1 days. Shares of COE stock traded up $0.05 during trading hours on Wednesday, reaching $1.15. 23,412 shares of the company traded hands, compared to its average volume of 281,656. China Online Education Group has a 12-month low of $0.76…