Major Customers and Suppliers

12 Months Ended

Dec. 31, 2015

(18) Major Customers and Suppliers

Sales to major customers as a percentage of the respective segment's sales were as follows:



	Year Ended December 31,
	2015		2014		2013
Petroleum
Customer A	14	%	13	%	12	%
Nitrogen Fertilizer
Customer B	10	%	17	%	15	%
Customer C	14	%	10	%	13	%
	24	%	27	%	28	%

The petroleum segment obtained crude oil from one third-party supplier under a long-term supply agreement during 2015, 2014 and 2013. The crude oil purchased from this supplier is governed by a long-term contract. Volume contracted as a percentage of the total crude oil purchases (in barrels) for each of the periods was as follows:



	Year Ended December 31,
	2015		2014		2013
Petroleum
Supplier A	61	%	67	%	69	%