To calculate month-to-month ordinary costs, KAYAK will take all price ranges for on a monthly basis over the last yr for spherical-vacation flights from London to Atlanta, removes the highest 0.1% to account for outliers, after which you can can take the median of all values for each month. You https://share.evernote.com/note/9084e627-d437-a274-6940-7f82cab92cd7