Commission Implementing Decision (EU) 2017/1984 of 24 October 2017 determining, pursuant to Regulation (EU) No 517/2014 of the European Parliament and of the Council on fluorinated greenhouse gases, reference values for the period 1 January 2018 to 31 December 2020 for each producer or importer which has lawfully placed on the market hydrofluorocarbons from 1 January 2015 as reported under that Regulation (notified under document C(2017) 7080)