delivered in 2015 compared to seven delivered in 2014).
The increases were partially offset by lower net sales of approximately $350 million for the C-130 program due to fewer aircraft deliveries (21 aircraft delivered in 2015, compared to 24 delivered in 2014), lower sustainment activities and aircraft contract mix; approximately $200 million due to decreased volume and lower risk retirements on various programs; approximately $195 million for the F-16 program due to fewer deliveries (11 aircraft delivered in 2015, compared to 17 delivered in 2014); and approximately $190 million for the F-22 program as a result of decreased sustainment activities.
Aeronautics’ operating profit in 2015 increased $32 million, or 2%, compared to 2014.
Operating profit increased by approximately $240 million for F-35 production contracts due to increased volume and risk retirements; and approximately $40 million for the C-5 program due to increased risk retirements.
These increases were offset by lower operating profit of approximately $90 million for the F-22 program due to lower risk retirements; approximately $70 million for the C-130 program as a result of the reasons stated above for lower net sales; and approximately $80 million due to decreased volume and risk retirements on various programs.
Adjustments not related to volume, including net profit booking rate adjustments and other matters, were approximately $100 million higher in 2015 compared to 2014.
Backlog Backlog increased in 2016 compared to 2015 primarily due to higher orders on F-35 production and sustainment programs.
Backlog increased in 2015 compared to 2014 primarily due to higher orders on F-35 and C-130 programs.
Trends We expect Aeronautics’ 2017 net sales to increase in the low-double digit percentage range as compared to 2016 due to increased volume on the F-35 program.
Operating profit is expected to increase at a slightly lower percentage range, driven by the increased volume on the F-35 program, partially offset by contract mix that results in a slight decrease in operating margins between years.
Missiles and Fire Control Our MFC business segment provides air and missile defense systems; tactical missiles and air-to-ground precision strike weapon systems; logistics; fire control systems; mission operations support, readiness, engineering support and integration services; manned and unmanned ground vehicles; and energy management solutions.
MFC’s major programs include PAC-3, THAAD, Multiple Launch Rocket System, Hellfire, JASSM, Javelin, Apache, Sniper?, Low Altitude Navigation and Targeting Infrared for Night (LANTIRN?)
and Special Operations Forces Contractor Logistics Support Services (SOF CLSS).
In 2016 we submitted a bid for the Special Operations Forces Global Logistics Support Services (SOF GLSS) contract, which is a competitive follow-on contract to SOF CLSS.
We anticipate an award decision on the follow-on contract in mid-2017.
MFC’s operating results included the following (in millions):
## Table 0 ##
2016 compared to 2015 MFC’s net sales in 2016 decreased $162 million, or 2%, compared to 2015.
The decrease was attributable to lower net sales of approximately $205 million for air and missile defense programs due to decreased volume (primarily THAAD); and lower net sales of approximately $95 million due to lower volume on various programs.
These decreases were partially offset by a $75 million increase for tactical missiles programs due to increased deliveries (primarily Hellfire); and approximately $70 million for fire control programs due to increased volume (SOF CLSS).
MFC’s operating profit in 2016 decreased $264 million, or 21%, compared to 2015.
Operating profit decreased approximately $145 million for air and missile defense programs due to lower risk retirements (PAC-3 and THAAD) and a reserve for a contractual matter; approximately $45 million for tactical missiles programs due to lower risk retirements (Javelin); and approximately $45 million for fire control programs due to lower risk retirements (Apache) and program mix.
Adjustments not related to volume, including net profit booking rate adjustments and reserves, were about $225 million lower in 2016 compared to 2015.
Allocation of Purchase Price to Assets Acquired and Liabilities Assumed We accounted for the acquisition of Sikorsky as a business combination, which requires us to record the assets acquired and liabilities assumed at fair value.
The amount by which the purchase price exceeds the fair value of the net assets acquired is recorded as goodwill.
During the fourth quarter of 2016, we completed our appraisals and determined the fair values of the assets acquired and liabilities assumed upon acquisition of Sikorsky.
As a result of the completed valuation the significant adjustments to the carrying amounts were as follows: Goodwill, trademarks intangible assets and customer programs intangible assets increased by about $78 million, $71 million and $57 million and inventories, net was decreased by about $185 million.
The measurement period adjustments did not result in a significant adjustment to amortization expense for intangible assets during 2016.
The following table summarizes the fair values of the assets acquired and liabilities assumed at the acquisition date, including the refinements described in the previous paragraph (in millions):
## Table 1 ##
(a) Recorded in other noncurrent liabilities on our consolidated balance sheets.
Intangible assets related to customer programs were recognized for each major helicopter and aftermarket program and represent the aggregate value associated with the customer relationships, contracts, technology and tradenames underlying the associated program.
These intangible assets will be amortized on a straight-line basis over a weighted-average useful life of approximately 15 years.
The useful life is based on a period of expected cash flows used to measure the fair value of each of intangible assets.
Customer contractual obligations represent liabilities on certain development programs where the expected costs exceed the expected sales under contract.
We measured these liabilities based on the price to transfer the obligation to a market participant at the measurement date, assuming that the liability will remain outstanding in the marketplace.
Based on the estimated net cash outflows of the developmental programs plus a reasonable contracting profit margin required to transfer the contracts to market participants, we recorded assumed liabilities of $507 million.
These liabilities will be liquidated in accordance with the underlying economic pattern of the contractual obligations, as reflected by the estimated future net cash outflows incurred on the associated contracts.
From the acquisition date through the year ended December 31, 2016, we recognized approximately $130 million in sales related to customer contractual obligations.
Estimated liquidation of the customer contractual obligation is approximated as follows: $110 million in 2017, $70 million in 2018, $70 million in 2019, $60 million in 2020, $40 million in 2021 and $27 million thereafter.
The fair values of the assets acquired and liabilities assumed were determined using income, market and cost valuation methodologies.
The fair value measurements were estimated using significant inputs that are not observable in the market and thus represent a Level 3 measurement as defined in Accounting Standards Codification (ASC) 820, Fair Value Measurement.
The income approach was primarily used to value the customer programs and trademarks intangible assets.
Our reconciliation of the 35% U. S.  federal statutory income tax rate to actual income tax expense for continuing operations is as follows (dollars in millions):
## Table 2 ##
(a) Includes one-time charge due primarily to the re-measurement of certain net deferred tax assets using the lower U. S.  corporate income tax rate and a deemed repatriation tax.
(b) Includes a reduction in our 2017 manufacturing benefit as a result of our decision to accelerate contributions to our pension fund in 2018.
In 2016, we adopted the accounting standard update for employee share-based payment awards on a prospective basis.
Accordingly, we recognized additional income tax benefits of $106 million and $152 million during the years ended December 31, 2017 and 2016.
The 2016 income tax rate also benefited from the nontaxable gain recorded in connection with the consolidation of AWE.
Tax benefits from the U. S.  manufacturing deduction were insignificant in 2017, $117 million in 2016, and $123 million in 2015.
We recognized tax benefits of $115 million in 2017, $107 million in 2016, and $70 million in 2015 from U. S.  research and development (R&D) tax credits, including benefits attributable to prior periods.
We receive a tax deduction for dividends paid on shares of our common stock held by certain of our defined contribution plans with an employee stock ownership plan feature.
The amount of the tax deduction has increased as we increased our dividend over the last three years, partially offset by a decline in the number of shares in these plans.
As a result of a decision in 2015 to divest our LMCFT business (see “Note 3 – Acquisitions and Divestitures”), we recorded an asset impairment charge of approximately $90 million.
This charge was partially offset by a net deferred tax benefit of about $80 million.
The net impact of the resulting tax benefit reduced the effective income tax rate by 1.2 percentage points in 2015.
We participate in the IRS Compliance Assurance Process program.
Examinations of the years 2015, 2016, and 2017 remain under IRS review.

Tables referenced above, in order (Table 0 first):
<table><tr><td></td><td>2016</td><td>2015</td><td>2014</td></tr><tr><td>Net sales</td><td>$6,608</td><td>$6,770</td><td>$7,092</td></tr><tr><td>Operating profit</td><td>1,018</td><td>1,282</td><td>1,344</td></tr><tr><td>Operating margin</td><td>15.4%</td><td>18.9%</td><td>19.0%</td></tr><tr><td>Backlog atyear-end</td><td>$14,700</td><td>$15,500</td><td>$13,300</td></tr></table>
<table><tr><td>Cash and cash equivalents</td><td>$ 75</td></tr><tr><td>Receivables, net</td><td>1,924</td></tr><tr><td>Inventories, net</td><td>1,632</td></tr><tr><td>Other current assets</td><td>46</td></tr><tr><td>Property, plant and equipment</td><td>649</td></tr><tr><td>Goodwill</td><td>2,842</td></tr><tr><td>Intangible assets:</td><td></td></tr><tr><td>Customer programs</td><td>3,184</td></tr><tr><td>Trademarks</td><td>887</td></tr><tr><td>Other noncurrent assets</td><td>572</td></tr><tr><td>Deferred income taxes, noncurrent</td><td>256</td></tr><tr><td>Total identifiable assets and goodwill</td><td>12,067</td></tr><tr><td>Accounts payable</td><td>-565</td></tr><tr><td>Customer advances and amounts in excess of costs incurred</td><td>-1,197</td></tr><tr><td>Salaries, benefits, and payroll taxes</td><td>-105</td></tr><tr><td>Other current liabilities</td><td>-430</td></tr><tr><td>Customer contractual obligations<sup>(a)</sup></td><td>-507</td></tr><tr><td>Other noncurrent liabilities</td><td>-185</td></tr><tr><td>Total liabilities assumed</td><td>-2,989</td></tr><tr><td>Total consideration</td><td>$ 9,078</td></tr></table>
<table><tr><td></td><td colspan="2">2017</td><td colspan="2">2016</td><td colspan="2">2015</td></tr><tr><td></td><td>Amount</td><td>Rate</td><td>Amount</td><td>Rate</td><td>Amount</td><td>Rate</td></tr><tr><td>Income tax expense at the U.S. federal statutory tax rate</td><td>$1,844</td><td>35.0%</td><td>$1,710</td><td>35.0%</td><td>$1,505</td><td>35.0%</td></tr><tr><td>Deferred tax write down and transition tax<sup>(a)</sup></td><td>1,862</td><td>35.3</td><td>—</td><td>—</td><td>—</td><td>—</td></tr><tr><td>Excess tax benefits for share-based payment awards</td><td>-106</td><td>-2.0</td><td>-152</td><td>-3.1</td><td>—</td><td>—</td></tr><tr><td>U.S. manufacturing deduction benefit<sup>(b)</sup></td><td>-7</td><td>-0.1</td><td>-117</td><td>-2.4</td><td>-123</td><td>-2.9</td></tr><tr><td>Research and development tax credit</td><td>-115</td><td>-2.2</td><td>-107</td><td>-2.2</td><td>-70</td><td>-1.6</td></tr><tr><td>Tax deductible dividends</td><td>-94</td><td>-1.8</td><td>-92</td><td>-1.9</td><td>-87</td><td>-2.0</td></tr><tr><td>Other, net</td><td>-44</td><td>-0.8</td><td>-109</td><td>-2.2</td><td>-52</td><td>-1.2</td></tr><tr><td>Income tax expense</td><td>$3,340</td><td>63.4%</td><td>$1,133</td><td>23.2%</td><td>$1,173</td><td>27.3%</td></tr></table>

Question: What is the average value of Income tax expense in in 2015,2016,and 2017?
Answer: 1882
Reasoning program: add(3340,1133), add(#0,1173), divide(#1,const_3)