notes to the consolidated financial statements union pacific corporation and subsidiary companies for purposes of this report , unless the context otherwise requires , all references herein to the 201ccorporation 201d , 201ccompany 201d , 201cupc 201d , 201cwe 201d , 201cus 201d , and 201cour 201d mean union pacific corporation and its subsidiaries , including union pacific railroad company , which will be separately referred to herein as 201cuprr 201d or the 201crailroad 201d . 1 . nature of operations operations and segmentation 2013 we are a class i railroad operating in the u.s . our network includes 32070 route miles , linking pacific coast and gulf coast ports with the midwest and eastern u.s . gateways and providing several corridors to key mexican gateways . we own 26053 miles and operate on the remainder pursuant to trackage rights or leases . we serve the western two-thirds of the country and maintain coordinated schedules with other rail carriers for the handling of freight to and from the atlantic coast , the pacific coast , the southeast , the southwest , canada , and mexico . export and import traffic is moved through gulf coast and pacific coast ports and across the mexican and canadian borders . the railroad , along with its subsidiaries and rail affiliates , is our one reportable operating segment . although we provide and analyze revenue by commodity group , we treat the financial results of the railroad as one segment due to the integrated nature of our rail network . the following table provides freight revenue by commodity group: .
what is the percent of our network route miles that is owned rather than operated on pursuant to trackage rights or leases
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 . basis of presentation 2013 the consolidated financial statements are presented in accordance with accounting principles generally accepted in the u.s . ( gaap ) as codified in the financial accounting standards board ( fasb ) accounting standards codification ( asc ) . 2 . significant accounting policies principles of consolidation 2013 the consolidated financial statements include the accounts of union pacific corporation and all of its subsidiaries . investments in affiliated companies ( 20% ( 20 % ) to 50% ( 50 % ) owned ) are accounted for using the equity method of accounting . all intercompany transactions are eliminated . we currently have no less than majority-owned investments that require consolidation under variable interest entity requirements . cash and cash equivalents 2013 cash equivalents consist of investments with original maturities of three months or less . accounts receivable 2013 accounts receivable includes receivables reduced by an allowance for doubtful accounts . the allowance is based upon historical losses , credit worthiness of customers , and current economic conditions . receivables not expected to be collected in one year and the associated allowances are classified as other assets in our consolidated statements of financial position. .