Commission Implementing Decision (EU) 2017/1985 of 31 October 2017 allowing targets in the key performance area of cost-efficiency for the years 2017, 2018 and 2019 for air navigation services of Malta, Bulgaria, and Poland to be revised in accordance with Article 17(1) of Implementing Regulation (EU) No 390/2013 (notified under document C(2017) 7121) (Text with EEA relevance. )$