management 2019s discussion and analysis of financial condition and results of operations 2013 ( continued ) ( amounts in millions , except per share amounts ) operating income increased during 2017 when compared to 2016 , comprised of a decrease in revenue of $ 42.1 , as discussed above , a decrease in salaries and related expenses of $ 28.0 and a decrease in office and general expenses of $ 16.9 . the decrease in salaries and related expenses was primarily due to lower discretionary bonuses and incentive expense as well as a decrease in base salaries , benefits and tax . the decrease in office and general expenses was primarily due to decreases in adjustments to contingent acquisition obligations , as compared to the prior year . operating income increased during 2016 when compared to 2015 due to an increase in revenue of $ 58.8 , as discussed above , and a decrease in office and general expenses of $ 3.7 , partially offset by an increase in salaries and related expenses of $ 38.8 . the increase in salaries and related expenses was attributable to an increase in base salaries , benefits and tax primarily due to increases in our workforce to support business growth over the last twelve months . the decrease in office and general expenses was primarily due to lower production expenses related to pass-through costs , which are also reflected in revenue , for certain projects in which we acted as principal that decreased in size or did not recur during the current year . corporate and other certain corporate and other charges are reported as a separate line item within total segment operating income and include corporate office expenses , as well as shared service center and certain other centrally managed expenses that are not fully allocated to operating divisions . salaries and related expenses include salaries , long-term incentives , annual bonuses and other miscellaneous benefits for corporate office employees . office and general expenses primarily include professional fees related to internal control compliance , financial statement audits and legal , information technology and other consulting services that are engaged and managed through the corporate office . office and general expenses also include rental expense and depreciation of leasehold improvements for properties occupied by corporate office employees . a portion of centrally managed expenses are allocated to operating divisions based on a formula that uses the planned revenues of each of the operating units . amounts allocated also include specific charges for information technology-related projects , which are allocated based on utilization . corporate and other expenses decreased during 2017 by $ 20.6 to $ 126.6 compared to 2016 , primarily due to lower annual incentive expense . corporate and other expenses increased during 2016 by $ 5.4 to $ 147.2 compared to 2015 . liquidity and capital resources cash flow overview the following tables summarize key financial data relating to our liquidity , capital resources and uses of capital. .

years ended december 31 , 2017: net income adjusted to reconcile to net cash provided by operating activities1: 887.3
net cash used in working capital2: -29.9
changes in other non-current assets and liabilities: 24.4
net cash provided by operating activities: 881.8
net cash used in investing activities: -196.2
net cash used in financing activities: -1004.9
years ended december 31 , 2016: net income adjusted to reconcile to net cash provided by operating activities1: 1023.2
net cash used in working capital2: -414.9
changes in other non-current assets and liabilities: -95.5
net cash provided by operating activities: 512.8
net cash used in investing activities: -263.9
net cash used in financing activities: -666.4
years ended december 31 , 2015: net income adjusted to reconcile to net cash provided by operating activities1: 848.8
net cash used in working capital2: -99.9
changes in other non-current assets and liabilities: -60.4
net cash provided by operating activities: 688.5
net cash used in investing activities: -199.7
net cash used in financing activities: -490.9

1 reflects net income adjusted primarily for depreciation and amortization of fixed assets and intangible assets , amortization of restricted stock and other non-cash compensation , net losses on sales of businesses and deferred income taxes . 2 reflects changes in accounts receivable , expenditures billable to clients , other current assets , accounts payable and accrued liabilities . operating activities due to the seasonality of our business , we typically use cash from working capital in the first nine months of a year , with the largest impact in the first quarter , and generate cash from working capital in the fourth quarter , driven by the seasonally strong media spending by our clients . quarterly and annual working capital results are impacted by the fluctuating annual media spending budgets of our clients as well as their changing media spending patterns throughout each year across various countries. .

Questions:
what was the total of corporate and other expenses in 2015?
and what was it in 2016?
what was, then, the combined total of corporate and other expenses for both of those years?
including corporate and other expenses from 2017, what would then be the total for three years?

Answers:
141.8
147.2
289
415.6