Table:
|  | NOTE | 2019 | 2018 |
| --- | --- | --- | --- |
| Balance, January 1 |  | (51) | (54) |
| Adoption of IFRS 9 |  | – | (4) |
| Additions |  | (114) | (84) |
| Usage |  | 103 | 91 |
| Balance, December 31 | 10 | (62) | (51) |
Paragraphs:
CREDIT RISK
We are exposed to credit risk from operating activities and certain financing activities, the maximum exposure of which is represented by the carrying amounts reported in the statements of financial position.
We are exposed to credit risk if counterparties to our trade receivables and derivative instruments are unable to meet their obligations. The concentration of credit risk from our customers is minimized because we have a large and diverse customer base. There was minimal credit risk relating to derivative instruments at December 31, 2019 and 2018. We deal with institutions that have investment-grade credit ratings, and as such we expect that they will be able to meet their obligations. We regularly monitor our credit risk and credit exposure.
The following table provides the change in allowance for doubtful accounts for trade receivables.
Question:
What are the periods considered in this context?
Answer: 2019, 2018