For the purpose of the review referred to in Article 23 and by 9 November 2018, and every two years thereafter, Member States shall submit to the Commission the information necessary to enable the Commission to assess the implementation of this Directive, in particular the consistency of Member States' approaches to the identification of operators of essential services. That information shall include at least:
(a) national measures allowing for the identification of operators of essential services;
(b) the list of services referred to in paragraph 3;
(c) the number of operators of essential services identified for each sector referred to in Annex II and an indication of their importance in relation to that sector;
(d) thresholds, where they exist, to determine the relevant supply level by reference to the number of users relying on that service as referred to in point (a) of Article 6(1) or to the importance of that particular operator of essential services as referred to in point (f) of Article 6(1).