[support] excessive bandwith usage

Greetings all, My site appears to be using too much bandwith. Iam on a shared hosting server and my provider has told me I am using in excess of 16% whilst I am only allowed 3% It also appears there about 50,000 visitors a day to the site which is a bit alrming as I have less than 300 members, What modules or scripts do you guys think are causing this excessive bandwith usage? I am running drupal 4.63 regards Larry