the given chart illisturates the number of complaints received by the complaints department of a single airline over a six-month period in 2009 .
as is observed , the number of complaints in person was moving upward sharply , while the number of complaints by email/fax was dropping slightly over the period in 2009.
it is obvious that the number of complaints in person reached the peak that was nearly 2000 in june. in january, the number of complaints by telephone was about 850 , then it was rising and the number of complaints by telephone was almost doubled which was 1600 in june .
the number of complaints in person was practically the same as the number of complaints by email/fax between february and march . the number of complaints decreased from 800 to 400 in six month . the number of complaints by telephone was more than two times of the number of complaints in person in january .
