 National HealthCare Co. NYSEAMERICAN:NHC was the recipient of a significant decline in short interest during the month of June. As of June 15th, there was short interest totalling 177,500 shares, a decline of 15.2 from the May 31st total of 209,200 shares. Based on an average daily trading volume, of 62,100 shares, the days-to-cover ratio ... 