MARATHON OIL CORPORATION Notes to Consolidated Financial Statements The following table sets forth quantitative information by category of derivative instrument at December 31, 2008 and 2007.
These amounts are reported on a gross basis by individual derivative instrument.
## Table 0 ##
(a) There was no ineffectiveness associated with fair value hedges for 2008 or 2007 because the hedging instruments and the existing firm commitment contracts were priced on the same underlying index.
Derivative instruments used in the fair value hedges mature in 2009.
(b) The contract price under the U. K.  natural gas contracts is reset annually and is indexed to a basket of costs of living and energy commodity indices for the previous 12 months.
The fair value of these contracts is determined by applying the difference between the contract price and the U. K.  forward natural gas strip price to the expected sales volumes under these contracts.
The U. K.  natural gas contracts expire September, 2009.
(c) Certain physical commodity contracts were classified as derivative instruments in 2007 because certain volumes covered by these contracts were physically netted at particular delivery locations.
The netting process caused all contracts at such delivery locations to be considered derivative instruments.
Other physical contracts that we chose not to designate as normal purchases or normal sales in that period were also been accounted for as derivative instruments.
Beginning in the second quarter of 2008, we ceased netting volumes and elected the normal purchase and normal sale designation for our physical commodity contracts; therefore reducing substantially our number of derivative instruments.
(d) The fair value of OTC interest rate swaps excludes accrued interest amounts not yet settled.
As of December 31, 2008, and 2007, accrued interest was a receivable of $1 million and a payable of $3 million.
The net fair value of the OTC interest rate swaps as of December 31, 2008 and 2007 is included in long-term debt.
See Note 20.
(e) The changes in fair value of cash flow hedges included less than $1 million ineffectiveness during 2008 and no ineffectiveness during 2007.19.
Short Term Debt We have a commercial paper program that is supported by the unused and available credit on our revolving credit facility discussed in Note 20.
At December 31, 2008 and 2007, there were no commercial paper borrowings outstanding
Acreage The following tables set forth, by geographic area, the developed and underdeveloped exploration and production acreage that we hold as of December 31, 2008.
Gross and Net Acreage
## Table 1 ##
Oil Sands Mining Through our acquisition of Western, we hold a 20 percent outside-operated interest in the AOSP, an oil sands mining joint venture located in Alberta, Canada.
The joint venture produces bitumen from oil sands deposits in the Athabasca region and upgrades the bitumen to synthetic crude oil.
The AOSP’s asset is the mining and extraction operations of the Muskeg River mine located near Fort McMurray, Alberta, which began bitumen production in 2003, together with Scotford upgrading infrastructure located northeast of Edmonton, Alberta.
The underlying developed leases are held for the duration of the project, with royalties paid to the province of Alberta.
As of December 31, 2008, we have rights to participate in developed and undeveloped leases totaling approximately 215,000 gross (45,000 net) acres.
Prior to December 6, 2009, we are entitled to participate in any new land acquisitions by either of the other AOSP owners within a defined area of mutual interest.
Current AOSP operations use established processes to mine oil sands deposits from an open-pit mine, extract the bitumen and upgrade it into synthetic crude oils.
Bitumen production from the mine is taken by pipeline to the Scotford upgrader.
Ore is mined using traditional truck and shovel mining techniques.
The mined ore passes through primary crushers to reduce the ore chunks in size and is then sent to rotary breakers where the chunks are further reduced to smaller particles.
The particles are combined with hot water to create slurry.
The slurry moves through a pipeline where it separates into sand, clay and bitumen.
Air is introduced to the slurry mixture, which creates a bitumen-rich froth.
A solvent is added to the bitumen froth to separate out the remaining solids, water and heavy asphaltenes.
The solvent washes the sand and produces clean bitumen that is required for the upgrader to run efficiently.
The process yields a mixture of solvent and bitumen, referred to as “dilbit”, which is then transported from the mine to the Scotford upgrader via the approximately 300 mile Corridor Pipeline.
The bitumen is upgraded at Scotford using both hydro-treating and a hydro-conversion process to remove sulfur and break the heavy carbon molecules into lighter products.
The three major products that the Scotford upgrader produces are Premium Albian synthetic crude oil, Albian Heavy synthetic crude oil and vacuum gas oil.
The vacuum gas oil is sold to the operator under a long term contract at market-related prices, and the other products are sold in the marketplace.
The following table sets forth key operating statistics for the last two years.
## Table 2 ##
(a) The oil sands mining operations were acquired October 18, 2007.
Daily volumes for 2007 represent total volumes since the acquisition date over total days in the period.
(b) Bitumen production is before royalties.
approximately 710 asphalt-paving contractors, government entities (states, counties, cities and townships) and asphalt roofing shingle manufacturers.
We also produce asphalt cements, polymerized asphalt, asphalt emulsions and industrial asphalts.
Retail Marketing SSA, our wholly-owned subsidiary, sells gasoline and merchandise through owned and operated retail outlets primarily under the Speedway?
and SuperAmerica?
brands.
Diesel fuel is also sold at a number of these outlets.
SSA retail outlets offer a wide variety of merchandise, such as prepared foods, beverages, and non-food items, as well as a significant number of proprietary items.
As of December 31, 2008, SSA had 1,617 retail outlets in nine states.
Sales of refined products through these retail outlets accounted for 15 percent of our refined product sales volumes in 2008.
Revenues from sales of non-petroleum merchandise through these retail outlets totaled $2,838 million in 2008, $2,796 million in 2007 and $2,706 million in 2006.
The demand for gasoline is seasonal in a majority of SSA markets, usually with the highest demand during the summer driving season.
Profit levels from the sale of merchandise and services tend to be less volatile than profit levels from the retail sale of gasoline and diesel fuel.
In October 2008, we sold our interest in Pilot Travel Centers LLC (“PTC”), an operator of travel centers in the United States.
Pipeline Transportation We own a system of pipelines through Marathon Pipe Line LLC (“MPL”) and Ohio River Pipe Line LLC (“ORPL”), our wholly-owned subsidiaries.
Our pipeline systems transport crude oil and refined products primarily in the Midwest and Gulf Coast regions to our refineries, our terminals and other pipeline systems.
Our MPL and ORPL wholly-owned and undivided interest common carrier systems consist of 1,815 miles of crude oil lines and 1,826 miles of refined product lines comprising 34 systems located in 11 states.
The MPL common carrier pipeline network is one of the largest petroleum pipeline systems in the United States, based on total barrels delivered.
Our common carrier pipeline systems are subject to state and Federal Energy Regulatory Commission regulations and guidelines, including published tariffs for the transportation of crude oil and refined products.
Third parties generated 11 percent of the crude oil and refined product shipments on our MPL and ORPL common carrier pipelines in 2008.
Our MPL and ORPL common carrier pipelines transported the volumes shown in the following table for each of the last three years.
## Table 3 ##
We also own 176 miles of private crude oil pipelines and 850 miles of private refined products pipelines, and we lease 217 miles of common carrier refined product pipelines.
We have partial ownership interests in several pipeline companies that have approximately 780 miles of crude oil pipelines and 3,000 miles of refined products pipelines, including about 800 miles operated by MPL.
In addition, MPL operates most of our private pipelines and 985 miles of crude oil and 160 miles of natural gas pipelines owned by our E&P segment.
Our major refined product lines include the Cardinal Products Pipeline and the Wabash Pipeline.
The Cardinal Products Pipeline delivers refined products from Kenova, West Virginia, to Columbus, Ohio.
The Wabash Pipeline system delivers product from Robinson, Illinois, to various terminals in the area of Chicago, Illinois.
Other significant refined product pipelines owned and operated by MPL extend from: Robinson, Illinois, to Louisville, Kentucky; Garyville, Louisiana, to Zachary, Louisiana; and Texas City, Texas, to Pasadena, Texas.

Tables referenced above, in order (Table 0 first):
<table><tr><td></td><td colspan="2">2008</td><td colspan="2">2007</td></tr><tr><td><i>(In millions)</i></td><td>Assets</td><td>(Liabilities)</td><td>Assets</td><td>(Liabilities)</td></tr><tr><td> Commodity Instruments</td><td></td><td></td><td></td><td></td></tr><tr><td>Fair value hedges:<sup>(a)</sup></td><td></td><td></td><td></td><td></td></tr><tr><td>OTC commodity swaps</td><td>$–</td><td>$-12</td><td>$10</td><td>$-5</td></tr><tr><td>Non-hedge designation:</td><td></td><td></td><td></td><td></td></tr><tr><td>Exchange-traded commodity futures</td><td>279</td><td>-277</td><td>423</td><td>-506</td></tr><tr><td>Exchange-traded commodity options</td><td>16</td><td>-18</td><td>312</td><td>-287</td></tr><tr><td>OTC commodity swaps</td><td>25</td><td>-55</td><td>17</td><td>-26</td></tr><tr><td>OTC commodity options</td><td>65</td><td>-14</td><td>–</td><td>-136</td></tr><tr><td>U.K. natural gas contracts<sup>(b)</sup></td><td>–</td><td>-72</td><td>–</td><td>-291</td></tr><tr><td>Physical commodity contracts<sup>(c)</sup></td><td>–</td><td>–</td><td>271</td><td>-198</td></tr><tr><td> Financial Instruments</td><td></td><td></td><td></td><td></td></tr><tr><td>Fair value hedges:</td><td></td><td></td><td></td><td></td></tr><tr><td>OTC interest rate swaps<sup>(d)</sup></td><td>29</td><td>–</td><td>–</td><td>-3</td></tr><tr><td>Cash flow hedges:<sup>(e)</sup></td><td></td><td></td><td></td><td></td></tr><tr><td>OTC foreign currency forwards</td><td>$2</td><td>$-77</td><td>$12</td><td>$–</td></tr></table>
<table><tr><td></td><td colspan="2">Developed</td><td colspan="2">Undeveloped</td><td colspan="2">Developed andUndeveloped</td></tr><tr><td><i>(Thousands of acres)</i></td><td>Gross</td><td>Net</td><td>Gross</td><td>Net</td><td>Gross</td><td>Net</td></tr><tr><td>United States</td><td>1,318</td><td>1,035</td><td>1,612</td><td>1,169</td><td>2,930</td><td>2,204</td></tr><tr><td>Europe</td><td>493</td><td>393</td><td>1,555</td><td>617</td><td>2,048</td><td>1,010</td></tr><tr><td>Africa</td><td>12,978</td><td>2,151</td><td>2,787</td><td>654</td><td>15,765</td><td>2,805</td></tr><tr><td>Other International</td><td>—</td><td>—</td><td>2,535</td><td>1,471</td><td>2,535</td><td>1,471</td></tr><tr><td>WORLDWIDE</td><td>14,789</td><td>3,579</td><td>8,489</td><td>3,911</td><td>23,278</td><td>7,490</td></tr></table>
<table><tr><td><i>(Thousands of barrels per day)</i></td><td>2008</td><td>2007<sup>(a)</sup></td></tr><tr><td>Net bitumen production<sup>(b)</sup></td><td>25</td><td>4</td></tr><tr><td>Net synthetic crude sales</td><td>32</td><td>4</td></tr></table>
<table><tr><td><i>(Thousands of barrels per day)</i></td><td>2008</td><td>2007</td><td>2006</td></tr><tr><td>Crude oil trunk lines</td><td>1,405</td><td>1,451</td><td>1,437</td></tr><tr><td>Refined products trunk lines</td><td>960</td><td>1,049</td><td>1,101</td></tr><tr><td>TOTAL</td><td>2,365</td><td>2,500</td><td>2,538</td></tr></table>

Question: What's the sum of Refined products trunk lines of 2007, and United States of Developed andUndeveloped Gross ?
Answer: 3979
Reasoning program: add(1049.0,2930.0)