additionally , the latin american soft alloy extrusions business previously included in corporate was moved into the new transportation and construction solutions segment .the remaining engineered products and solutions segment consists of the alcoa fastening systems and rings ( renamed to include portions of the firth rixson business acquired in november 2014 ) , alcoa power and propulsion ( includes the tital business acquired in march 2015 ) , alcoa forgings and extrusions ( includes the other portions of firth rixson ) , and alcoa titanium and engineered products ( a new business unit that consists solely of the rti international metals business acquired in july 2015 ) business units .segment information for all prior periods presented was updated to reflect the new segment structure .atoi for all reportable segments totaled $ 1906 in 2015 , $ 1968 in 2014 , and $ 1267 in 2013 .the following information provides shipments , sales , and atoi data for each reportable segment , as well as certain production , realized price , and average cost data , for each of the three years in the period ended december 31 , 2015 .see note q to the consolidated financial statements in part ii item 8 of this form 10-k for additional information .alumina .
[['', '2015', '2014', '2013'], ['alumina production ( kmt )', '15720', '16606', '16618'], ['third-party alumina shipments ( kmt )', '10755', '10652', '9966'], ['alcoa 2019s average realized price per metric ton of alumina', '$ 317', '$ 324', '$ 328'], ['alcoa 2019s average cost per metric ton of alumina*', '$ 237', '$ 282', '$ 295'], ['third-party sales', '$ 3455', '$ 3509', '$ 3326'], ['intersegment sales', '1687', '1941', '2235'], ['total sales', '$ 5142', '$ 5450', '$ 5561'], ['atoi', '$ 746', '$ 370', '$ 259']]
* includes all production-related costs , including raw materials consumed ; conversion costs , such as labor , materials , and utilities ; depreciation , depletion , and amortization ; and plant administrative expenses .this segment represents a portion of alcoa 2019s upstream operations and consists of the company 2019s worldwide refining system .alumina mines bauxite , from which alumina is produced and then sold directly to external smelter customers , as well as to the primary metals segment ( see primary metals below ) , or to customers who process it into industrial chemical products .more than half of alumina 2019s production is sold under supply contracts to third parties worldwide , while the remainder is used internally by the primary metals segment .alumina produced by this segment and used internally is transferred to the primary metals segment at prevailing market prices .a portion of this segment 2019s third- party sales are completed through the use of agents , alumina traders , and distributors .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 australian dollar , the brazilian real , the u.s .dollar , and the euro .awac is an unincorporated global joint venture between alcoa and alumina limited and consists of a number of affiliated operating entities , which own , or have an interest in , or operate the bauxite mines and alumina refineries within the alumina segment ( except for the poc 0327os de caldas refinery in brazil and a portion of the sa 0303o lul 0301s refinery in brazil ) .alcoa owns 60% ( 60 % ) and alumina limited owns 40% ( 40 % ) of these individual entities , which are consolidated by the company for financial reporting purposes .as such , the results and analysis presented for the alumina segment are inclusive of alumina limited 2019s 40% ( 40 % ) interest .in december 2014 , awac completed the sale of its ownership stake in jamalco , a bauxite mine and alumina refinery joint venture in jamaica , to noble group ltd .jamalco was 55% ( 55 % ) owned by a subsidiary of awac , and , while owned by awac , 55% ( 55 % ) of both the operating results and assets and liabilities of this joint venture were included in the alumina segment .as it relates to awac 2019s previous 55% ( 55 % ) ownership stake , the refinery ( awac 2019s share of the capacity was 779 kmt-per-year ) generated sales ( third-party and intersegment ) of approximately $ 200 in 2013 , and the refinery and mine combined , at the time of divestiture , had approximately 500 employees .see restructuring and other charges in results of operations above. .

Question: what is the percentual reduction of intersegment sales concerning the total sales during 2013 and 2014?
Answer: 4.58%
Explanation: it is the difference between the percentage of intersegment sales concerning total sales in 2013 ( 40.19% ) and 2014 ( 35.61% )