| Day | Rate | Set date |
|---|---|---|
| 1 May | 18.8000 | .. |
| 2 May | 18.7900 | .. |
| 3 May | 19.1700 | .. |
| 7 May | 19.3600 | .. |
| 8 May | 19.3000 | .. |
| 9 May | 18.8000 | .. |
| 10 May | 19.0500 | .. |
| 13 May | 19.3300 | .. |
| 14 May | 19.3500 | .. |
| 15 May | 19.3000 | .. |
| 16 May | 18.6900 | .. |
| 17 May | 17.5400 | .. |
| 20 May | 18.6100 | .. |
| 21 May | 18.4200 | .. |
| 22 May | 19.0600 | .. |
| 23 May | 18.8900 | .. |
| 24 May | 19.1000 | .. |
| 28 May | 18.9400 | .. |
| 29 May | 18.6300 | .. |
| 30 May | 17.8900 | .. |
| 31 May | 17.8000 | .. |