although our revenues are principally derived from customers domiciled in the u.s. , the ultimate points of origination or destination for some products we transport are outside the u.s . each of our commodity groups includes revenue from shipments to and from mexico . included in the above table are freight revenues from our mexico business which amounted to $ 2.2 billion in 2016 , $ 2.2 billion in 2015 , and $ 2.3 billion in 2014