Ukraine after the completion of the heating season 2015/2016 has increased natural gas stocks at Ukraine's underground storage facilities, public joint-stock company Ukrtransgaz has reported.If on April 6 8.438 bcm of gas were in the underground storage facilities, then on September 10 gas stocks amounted to 13.112 bcm.Naftogaz Ukrainy top managers earlier that the holding seeks to start the new heating season with gas stocks of at least 14.5 bcm.