Band 9: The line graph below shows the number of complaints received by the complaints department of a single airline over a six-month period in 2009. Summarise the information by selecting and reporting the main features making comparisons where relevant.

The line graph illustrates the number of complaints received by the complaints department of a specific airline from January to June. It is evident that the number of complaints made in person and by telephone tended to increase throughout the entire period. In contrast, complaints sent via email or fax exhibited a downward trend over the course of six months.

In the first two months, the number of complaints made by telephone declined slightly but then rose again. This figure remained consistent for the next two months. Notably, it peaked in June, increasing from about 1,000 to exactly 1,600 by the end of the period. Meanwhile, complaints made in person started at over 400 in January and increased steadily to approximately 800 in March. Ultimately, this figure reached its highest point of over 1,800 by the end of the period.

Conversely, complaints sent via email or fax began at nearly 800 in January but gradually declined until May. In the final month, the number of complaints remained unchanged for the duration of the period.