Fuel Costs

Ok, sorry if I have posted this in the wrong place, but it is my first Topic. I was watching CNN video's this morning and they were talking about a trucking company that is going across the border to Mexico to by there diesel fuel. The fuel is only 2.00 per gallon just accross the border! So I would like for gather some information and I am asking for everyone's help.
1) How many refineries are there in the U.S. and how many in Mexico.
2) What is the annual usage for both the U.S. and Mexico.
3) Why is it so much cheaper than the U.S.???
Link to the news viedo
www.cnn.com...#/video/us/2008/04/23/dnt.az.buying.diesel.mexico.ktvk