The cost of inventories recognized as an expense in respect of operating income was Ps. 3,290,994, Ps. 1,280,829 and Ps. 958,469 for the periods of 2020, 2019 and 2018.

The cost of inventories recognized as an expense includes Ps. 24,438, Ps. 14,273 and Ps. 7,084 for the periods of 2020, 2019 and 2018, respectively, in respect of write-downs of inventory to net realizable value. Such write-downs have been recognized to account for obsolete inventories.