How is the bunker adjustment in international trade calculated?

The Bunker Adjustment Factor (BAF), also known as the Currency and Bunker Adjustment Factor (CABAF - sea freight), is applied by shipping lines or liner conferences to offset the effect of fluctuations in the cost of bunkers (oil). Here is the best Web site to visit for a complete explanation of BAF calculations: http://www.export911.com/e911/ship/w_or_m.htm