Table:
|  | Credit Rating | Authorised Limit | Group Exposure 31 December 2019 | Credit Rating | Authorised Limit | Group Exposure 31 December 2018 |
| --- | --- | --- | --- | --- | --- | --- |
|  |  | £m | £m |  | £m | £m |
| Counterparty #1 | AA- | 125.0 | 64.9 | AA- | 125.0 | 111.9 |
| Counterparty #2 | AAA | 150.0 | 43.1 | A+ | 100.0 | 44.1 |
| Counterparty #3 | A+ | 100.0 | 38.7 | A | 100.0 | 27.2 |
| Counterparty #4 | A | 100.0 | 26.0 | AAA | 150.0 | 22.3 |
| Counterparty #5 | A | 75.0 | 20.0 | AAA | 150.0 | 12.3 |
| Sum of five largest exposures |  |  | 192.7 |  |  | 217.8 |
| Sum of cash deposits and derivative financial instrument assets |  |  | 203.5 |  |  | 244.2 |
| Five largest exposures as a percentage of assets at risk |  |  | 95% |  |  | 89% |
Paragraphs:
At 31 December 2019 trade receivables are shown net of a loss allowance totalling £6.1 million (2018: £4.0 million).
The Group does not use factoring to generate cash flow from trade receivables.
– other financial assets including loans to joint ventures
The Group applies the expected credit loss model in respect of other financial assets. Financial assets are individually assessed as to whether the credit risk has increased significantly in the period and therefore whether there is a need to apply the lifetime expected credit losses model as opposed to the 12-month expected credit loss model.
At 31 December 2019 there is no loss allowance recognised for other financial assets as it has been concluded as an immaterial risk of credit loss on other financial assets.
– cash deposits and derivative financial instruments
The credit risk relating to cash deposits and derivative financial instruments is actively managed by the Group’s treasury department. Relationships are maintained with a number of tier one institutional counterparties, ensuring compliance with Group policy relating to limits on the credit ratings of counterparties (between BBB+ and AAA).
Excessive credit risk concentration is avoided through adhering to authorised limits for all counterparties.
Question:
What is the percentage change in the sum of cash deposits and derivative financial instrument assets from 2018 to 2019?
Answer: (203.5-244.2)/244.2 = -16.67