Table:
| USDm | 2019 | 2018 | 2017 |
| --- | --- | --- | --- |
| Allowance for expected credit loss |  |  |  |
| Balance as of 1 January | 1.7 | 1.3 | 2.6 |
| Adjustment to prior years | 1.5 | - | - |
| Provisions for the year | 2.4 | 1.7 | 0.6 |
| Provisions reversed during the year | -1.9 | -1.0 | -1.9 |
| Provisions utilized during the year | - | -0.3 | - |
| Balance as of 31 December | 3.7 | 1.7 | 1.3 |
Paragraphs:
Management makes allowance for expected credit loss based on the simplified approach to provide for expected credit losses, which permits the use of the lifetime expected loss provision for all trade receivables. Expected credit loss for receivables overdue more than 180 days is 25%-100%, depending on category. Expected credit loss for receivables overdue more than one year is 100%.
Movements in provisions for impairment of freight receivables during the year are as follows:
Allowance for expected credit loss of freight receivables have been recognized in the income statement under "Port expenses, bunkers and commissions".
Allowance for expected credit loss of freight receivables is calculated using an ageing factor as well as a specific customer knowledge and is based on a provision matrix on days past due.
Question:
How is allowance for expected credit loss of freight receivables calculated?
Answer: using an ageing factor as well as a specific customer knowledge and is based on a provision matrix on days past due.