Commission Implementing Regulation (EU) 2017/1579 of 18 September 2017 establishing the allocation coefficient to be applied to the quantities covered by the applications for import licences lodged from 1 to 7 September 2017 and determining the quantities to be added to the quantity fixed for the subperiod from 1 January to 31 March 2018 under the tariff quotas opened by Regulation (EC) No 533/2007 in the poultrymeat sector