in 2016 , alumina production will be approximately 2500 kmt lower , mostly due to the curtailment of the point comfort and suralco refineries . also , the continued shift towards alumina index and spot pricing is expected to average 85% ( 85 % ) of third-party smelter-grade alumina shipments . additionally , net productivity improvements are anticipated . primary metals .

Table: 2015 2014 2013 aluminum production ( kmt ) 2811 3125 3550 third-party aluminum shipments ( kmt ) 2478 2534 2801 alcoa 2019s average realized price per metric ton of aluminum* $ 2069 $ 2405 $ 2243 alcoa 2019s average cost per metric ton of aluminum** $ 2064 $ 2252 $ 2201 third-party sales $ 5591 $ 6800 $ 6596 intersegment sales 2170 2931 2621 total sales $ 7761 $ 9731 $ 9217 atoi $ 155 $ 594 $ -20 ( 20 )

* average realized price per metric ton of aluminum includes three elements : a ) the underlying base metal component , based on quoted prices from the lme ; b ) the regional premium , which represents the incremental price over the base lme component that is associated with the physical delivery of metal to a particular region ( e.g. , the midwest premium for metal sold in the united states ) ; and c ) the product premium , which represents the incremental price for receiving physical metal in a particular shape ( e.g. , billet , slab , rod , etc. ) or alloy . **includes all production-related costs , including raw materials consumed ; conversion costs , such as labor , materials , and utilities ; depreciation and amortization ; and plant administrative expenses . this segment represents a portion of alcoa 2019s upstream operations and consists of the company 2019s worldwide smelting system . primary metals purchases alumina , mostly from the alumina segment ( see alumina above ) , from which primary aluminum is produced and then sold directly to external customers and traders , as well as to alcoa 2019s midstream operations and , to a lesser extent , downstream operations . results from the sale of aluminum powder , scrap , and excess energy are also included in this segment , as well as the results of aluminum derivative contracts and buy/ resell activity . primary aluminum produced by alcoa and used internally is transferred to other segments at prevailing market prices . the sale of primary aluminum represents approximately 90% ( 90 % ) of this segment 2019s third-party sales . buy/ resell activity occurs when this segment purchases metal and resells such metal to external customers or the midstream and downstream operations in order to maximize smelting system efficiency and to meet customer requirements . generally , the sales of this segment are transacted in u.s . dollars while costs and expenses of this segment are transacted in the local currency of the respective operations , which are the u.s . dollar , the euro , the norwegian kroner , icelandic krona , the canadian dollar , the brazilian real , and the australian dollar . in november 2014 , alcoa completed the sale of an aluminum rod plant located in b e9cancour , qu e9bec , canada to sural laminated products . this facility takes molten aluminum and shapes it into the form of a rod , which is used by customers primarily for the transportation of electricity . while owned by alcoa , the operating results and assets and liabilities of this plant were included in the primary metals segment . in conjunction with this transaction , alcoa entered into a multi-year agreement with sural laminated products to supply molten aluminum for the rod plant . the aluminum rod plant generated sales of approximately $ 200 in 2013 and , at the time of divestiture , had approximately 60 employees . see restructuring and other charges in results of operations above . in december 2014 , alcoa completed the sale of its 50.33% ( 50.33 % ) ownership stake in the mt . holly smelter located in goose creek , south carolina to century aluminum company . while owned by alcoa , 50.33% ( 50.33 % ) of both the operating results and assets and liabilities related to the smelter were included in the primary metals segment . as it relates to alcoa 2019s previous 50.33% ( 50.33 % ) ownership stake , the smelter ( alcoa 2019s share of the capacity was 115 kmt-per-year ) generated sales of approximately $ 280 in 2013 and , at the time of divestiture , had approximately 250 employees . see restructuring and other charges in results of operations above . at december 31 , 2015 , alcoa had 778 kmt of idle capacity on a base capacity of 3401 kmt . in 2015 , idle capacity increased 113 kmt compared to 2014 , mostly due to the curtailment of 217 kmt combined at a smelter in each the .

Question: what was the decrease in the number of dollars obtained with the sale of primary aluminum during 2013 and 2014?
Answer: 183.6
Calculation: subtract(multiply(6800, 90%), multiply(6596, 90%))
Explanation: it is the difference between the number of third-party sales of primary aluminum in 2014 and 2013 .