Band 8+: 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 an airline over six months, categorized by in-person, telephone, email, and fax methods. Overall, the number of in-person and telephone complaints rose significantly, whereas complaints via email and fax declined sharply. Notably, in-person complaints became the most frequent by the end of the period.

Looking at the details, in-person complaints started as the least common method, at approximately 400 per year, while telephone complaints were the highest at 1,000 annually. However, in-person complaints surged dramatically to 1,900 by June, surpassing all other methods. Similarly, telephone complaints also showed a sharp increase, reaching 1,400 by the end of the period.

In contrast, email complaints followed an entirely opposite trend. The number fell steadily from 800 to 400 per year over the six months. This decline was mirrored by fax complaints, which also saw a significant drop.