theme parks segment 2013 operating costs and expenses our theme parks segment operating costs and expenses consist primarily of theme park operations , includ- ing repairs and maintenance and related administrative expenses ; food , beverage and merchandise costs ; labor costs ; and sales and marketing costs . theme parks segment operating costs and expenses increased in 2015 and 2014 primarily due to additional costs at our orlando and hollywood theme parks associated with newer attractions , such as the fast fur- ious 2122 2014 supercharged 2122 studio tour in hollywood in 2015 and the wizarding world of harry potter 2122 2014 diagon alley 2122 in orlando in 2014 and increases in food , beverage and merchandise costs associated with the increases in attendance in both years . operating costs and expenses also increased in 2015 due to $ 89 million of operating costs and expenses attributable to universal studios japan and $ 22 million of transaction costs related to our development of a theme park in china . nbcuniversal headquarters , other and eliminations headquarters and other operating costs and expenses incurred by our nbcuniversal businesses include overhead , personnel costs and costs associated with corporate initiatives . operating costs and expenses increased in 2015 and 2014 primarily due to higher employee-related costs , including severance costs in corporate and other results of operations year ended december 31 ( in millions ) 2015 2014 2013 % (  % ) change 2014 to 2015 % (  % ) change 2013 to 2014 .

2015: revenue: 766
operating costs and expenses: 1664
operating loss before depreciation and amortization: -898
2014: revenue: 709
operating costs and expenses: 1487
operating loss before depreciation and amortization: -778
2013: revenue: 600
operating costs and expenses: 1089
operating loss before depreciation and amortization: -489
% (  % ) change 2014 to 2015: revenue: -8
operating costs and expenses: 11.9
operating loss before depreciation and amortization: -15.5
% (  % ) change 2013 to 2014: revenue: -18.1
operating costs and expenses: 36.5
operating loss before depreciation and amortization: -59.1

corporate and other 2013 revenue other revenue primarily relates to comcast spectacor , which owns the philadelphia flyers and the wells fargo center arena in philadelphia , pennsylvania and operates arena management-related businesses . other revenue increased in 2015 and 2014 primarily due to increases in revenue from food and other services associated with new contracts entered into by one of our comcast spectacor businesses . the increase in other revenue in 2014 was also due to an increase in revenue associated with newly acquired businesses . corporate and other 2013 operating costs and expenses corporate and other operating costs and expenses primarily include overhead , personnel costs , the costs of corporate initiatives and branding , and operating costs and expenses associated with comcast spectacor . excluding transaction costs associated with the time warner cable merger and related divestiture trans- actions of $ 178 million and $ 237 million in 2015 and 2014 , respectively , corporate and other operating costs and expenses increased 19% ( 19 % ) in 2015 . this was primarily due to $ 56 million of expenses related to a contract settlement , an increase in expenses related to corporate strategic business initiatives and an increase in operating costs and expenses at comcast spectacor primarily associated with new contracts entered into by one of its businesses . corporate and other operating costs and expenses increased in 2014 primarily due to $ 237 million of transaction-related costs associated with the time warner cable merger and related divest- iture transactions , as well as an increase in operating costs and expenses associated with new contracts entered into by one of our comcast spectacor businesses . comcast 2015 annual report on form 10-k 60 .

Questions:
what is the sum of revenues from 2015 and 2014?
what were revenues in 2013?
what is the total sum?
what is the average per year?

Answers:
1475
600
2075
691.7