Revenue from services rendered
The principal service revenue derives from monthly subscription, the provision of separate voice, SMS and data services, and user packages combining these services, roaming charges and interconnection revenue. The revenue is recognized as the services are used, net of sales taxes and discounts granted on services. This revenue is recognized only when the amount of services rendered can be estimated reliably.
The revenue is recognized monthly via invoicing, and billable revenue between the billing date and the end of the month (unbilled) are identified, processed and recognized in the month in which the service was rendered. Calculations of unbilled revenue from the previous month are reversed, and unbilled amounts are calculated at the end of each month, considering the revenue billed in the previous month.
Interconnection traffic and roaming revenue are recorded separately, without offsetting the amounts owed to other telecom operators (the latter are accounted for as operating costs).
The minutes not used by customers and/or top-up credits in the possession of commercial partners regarding the prepaid service system are recorded as deferred revenue and allocated to income when these services are actually used by customers.
Revenue from product sales
Revenue from product sales (telephones, mini-modems, tablets and other equipment) are recognized when the significant risks and benefits of the ownership of such products are transferred to the buyer.
| 2017 | 2016 | 2015 | ||||
| Service revenue – Mobile | 20,147,585 | 20,188,962 | 22,121,450 | |||
| Service revenue – Landline | 1,285,930 | 1,178,856 | 1,003,185 | |||
| Service revenue | 21,433,515 | 21,367,818 | 23,124,635 | |||
| Goods sold | 1,177,559 | 1,377,771 | 2,646,866 | |||
| Gross operating revenue | 22,611,074 | 22,745,589 | 25,771,501 | |||
| Deductions from gross revenue | ||||||
| Taxes | (5,027,406) | (5,694,886) | (6,248,310) | |||
| Discounts given | (1,329,600) | (1,394,223) | (2,213,041) | |||
| Returns and other | (20,109) | (39,067) | (167,885) | |||
| (6,377,115) | (7,128,176) | (8,629,236) | ||||
| Total revenue | 16,233,959 | 15,617,413 | 17,142,265 |