9.
Intangible Assets Intangible assets principally comprise technology/technical know-how, tradenames and customer relationships.
At December 31, the gross book value and accumulated amortization of intangible assets were as follows:
## Table 0 ##
Amortization expense was $190 million in 2010, $114 million in 2009 and $124 million in 2008.
The weighted average amortization period for all intangible assets is approximately 21 years.
Amortization expense for the subsequent five years is estimated to be as follows: 2011 – $323 million, 2012 – $316 million, 2013 – $298 million, 2014 – $292 million and 2015 – $277 million.10.
Long-term Debt and Debt Facility Agreements Long-term Debt consists of the following:
## Table 1 ##
(1) Represents long-term fixed rate debt obligations assumed in connection with the merger of Smith, net of amounts repurchased subsequent to the closing of the transaction.
The fair value adjustment presented above represents changes in the fair value of the portion of Schlumberger’s fixed rate debt that is hedged through the use of interest rate swaps.
During the third and fourth quarters of 2010, Schlumberger repurchased all of its $650 million 6.50% Notes due 2012.
During the first quarter of 2009, Schlumberger entered into a A3.0 billion Euro Medium Term Note program.
This program provides for the issuance of various types of debt instruments such as fixed or floating rate notes in euro, US dollar or other currencies.
Schlumberger issued A1.0 billion 2.75% Guaranteed Notes due 2015 in the fourth quarter of 2010 under this program.
Schlumberger entered into agreements to swap these euro notes for US dollars on the date of issue until maturity, effectively making this a US dollar denominated debt on which Schlumberger will pay interest in US dollars at a rate of 2.56%.
Schlumberger also issued A1.0 billion 4.50% Guaranteed Notes due 2014 in the first quarter of 2009 under this program.
Schlumberger entered into agreements to swap these euro notes for US dollars on the date of issue until maturity, effectively making this a US dollar denominated debt on which Schlumberger will pay interest in US dollars at a rate of 4.95%.
During the third quarter of 2009, Schlumberger issued $450 million of 3.00% Guaranteed Notes due 2013.
Reservoir Production Revenue of $12.75 billion was 41% higher than the same period last year while pretax operating margin increased 541 bps to 20.5%.
Well Services revenue and margins expanded strongly in North America on higher pricing, capacity additions and improved asset utilization and efficiency as the market transitioned to liquid-rich plays.
Internationally, Well Services also posted growth on the strength of higher activity, despite the exceptional geopolitical events which prevailed during the first quarter of 2011.
Distribution Revenue of $2.62 billion increased $1.85 billion, while pretax operating income of $103 million increased $74 million compared to last year.
These increases are attributable to the fact that 2010 reflected only four months of activity following the Smith acquisition.
Full-Year 2010 Results
## Table 2 ##
(1) Comprised principally of corporate expenses not allocated to the segments, interest on postretirement medical benefits, stock-based compensation costs, amortization expense associated with intangible assets recorded as a result of the acquisition of Smith and certain other nonoperating items.
(2) Excludes interest income included in the segments’ income (2010 – $7 million; 2009 – $10 million).
(3) Excludes interest expense included in the segments’ income (2010 – $5 million; 2009 – $33 million).
(4) Charges and credits are described in detail in Note 3 to the Consolidated Financial Statements.
Equity in Net Earnings of Affiliated Companies Equity income from the M-I SWACO joint venture in 2010 represents eight months of equity income through the closing of the Smith transaction.
Interest Expense Interest expense of $298 million in 2011 increased by $91 million compared to 2010 primarily due to the $4.6 billion of long-term debt that Schlumberger issued during 2011.
Interest expense of $207 million in 2010 decreased by $14 million compared to 2009 primarily due to a decline in the weighted average borrowing rates, from 3.9% to 3.2%.
Other Research & engineering and General & administrative expenses, as a percentage of Revenue, were as follows:

Tables referenced above, in order (Table 0 first):
<table><tr><td></td><td colspan="3"> 2010</td><td colspan="3"> 2009</td></tr><tr><td></td><td> Gross   Book Value</td><td> Accumulated   Amortization</td><td> Net Book   Value</td><td> Gross   Book Value</td><td> Accumulated   Amortization</td><td> Net Book   Value</td></tr><tr><td>Technology/Technical Know-How</td><td> $1,846</td><td> $215</td><td> $1,631</td><td>$527</td><td>$163</td><td>$364</td></tr><tr><td>Tradenames</td><td> 1,678</td><td> 61</td><td> 1,617</td><td>84</td><td>32</td><td>52</td></tr><tr><td>Customer Relationships</td><td> 1,963</td><td> 129</td><td> 1,834</td><td>355</td><td>80</td><td>275</td></tr><tr><td>Other</td><td> 378</td><td> 298</td><td> 80</td><td>376</td><td>281</td><td>95</td></tr><tr><td></td><td> $5,865</td><td> $703</td><td> $5,162</td><td>$1,342</td><td>$556</td><td>$786</td></tr></table>
<table><tr><td> As at December 31,</td><td> 2010</td><td> 2009</td></tr><tr><td>4.50% Guaranteed Notes due 2014</td><td>$1,319</td><td>$1,449</td></tr><tr><td>2.75% Guranteed Notes due 2015</td><td>1,310</td><td>–</td></tr><tr><td>5.25% Guaranteed Notes due 2013</td><td>659</td><td>727</td></tr><tr><td>9.75% Senior Notes due 2019<sup>-1</sup></td><td>776</td><td>–</td></tr><tr><td>3.00% Guaranteed Notes due 2013</td><td>450</td><td>449</td></tr><tr><td>8.625% Senior Notes due 2014<sup>-1</sup></td><td>272</td><td>–</td></tr><tr><td>6.00% Senior Notes due 2016<sup>-1</sup></td><td>218</td><td>–</td></tr><tr><td>6.5% Notes due 2012</td><td>–</td><td>649</td></tr><tr><td>5.875% Guaranteed Bonds due 2011</td><td>–</td><td>362</td></tr><tr><td>Commercial paper borrowings</td><td>367</td><td>358</td></tr><tr><td>Other variable rate debt</td><td>133</td><td>360</td></tr><tr><td></td><td>5,504</td><td>4,354</td></tr><tr><td>Fair value adjustment – hedging</td><td>13</td><td>1</td></tr><tr><td></td><td>$5,517</td><td>$4,355</td></tr></table>
<table><tr><td></td><td colspan="2">2010</td><td colspan="2">2009</td></tr><tr><td></td><td> Revenue</td><td>Income before taxes</td><td>Revenue</td><td>Income before taxes</td></tr><tr><td> <i>Oilfield Services</i></td><td></td><td></td><td></td><td></td></tr><tr><td>Reservoir Characterization</td><td>$9,321</td><td>$2,321</td><td>$9,502</td><td>$2,559</td></tr><tr><td>Drilling</td><td>8,230</td><td>1,334</td><td>5,881</td><td>1,245</td></tr><tr><td>Reservoir Production</td><td>9,053</td><td>1,368</td><td>7,282</td><td>780</td></tr><tr><td>Eliminations & other</td><td>69</td><td>48</td><td>37</td><td>51</td></tr><tr><td></td><td>26,673</td><td>5,071</td><td>22,702</td><td>4,635</td></tr><tr><td> <i>Distribution</i></td><td>774</td><td>29</td><td>–</td><td>–</td></tr><tr><td></td><td>774</td><td>29</td><td>–</td><td>–</td></tr><tr><td>Corporate & other<sup>-1</sup></td><td>–</td><td>-406</td><td>–</td><td>-327</td></tr><tr><td>Interest income<sup>-2</sup></td><td>–</td><td>43</td><td>–</td><td>52</td></tr><tr><td>Interest expense<sup>-3</sup></td><td>–</td><td>-202</td><td>–</td><td>-188</td></tr><tr><td>Charges & credits<sup>-4</sup></td><td>–</td><td>621</td><td>–</td><td>-238</td></tr><tr><td></td><td>$27,447</td><td>$5,156</td><td>$22,702</td><td>$3,934</td></tr><tr><td colspan="5">(Stated in millions)</td></tr><tr><td></td><td colspan="2">2010</td><td colspan="2">2009</td></tr><tr><td></td><td> Revenue</td><td>Income before taxes</td><td>Revenue</td><td>Income before taxes</td></tr><tr><td> <i>Oilfield Services</i></td><td></td><td></td><td></td><td></td></tr><tr><td>North America</td><td>$6,729</td><td>$1,145</td><td>$4,217</td><td>$387</td></tr><tr><td>Latin America</td><td>4,985</td><td>808</td><td>4,552</td><td>864</td></tr><tr><td>Europe/CIS/Africa</td><td>8,024</td><td>1,457</td><td>7,737</td><td>1,821</td></tr><tr><td>Middle East & Asia</td><td>6,650</td><td>1,764</td><td>5,961</td><td>1,817</td></tr><tr><td>Eliminations & other</td><td>285</td><td>-103</td><td>235</td><td>-254</td></tr><tr><td></td><td>26,673</td><td>5,071</td><td>22,702</td><td>4,635</td></tr><tr><td> <i>Distribution</i></td><td>774</td><td>29</td><td>–</td><td>–</td></tr><tr><td></td><td>774</td><td>29</td><td>–</td><td>–</td></tr><tr><td>Corporate & other<sup>-1</sup></td><td>–</td><td>-406</td><td>–</td><td>-327</td></tr><tr><td>Interest income<sup>-2</sup></td><td>–</td><td>43</td><td>–</td><td>52</td></tr><tr><td>Interest expense<sup>-3</sup></td><td>–</td><td>-202</td><td>–</td><td>-188</td></tr><tr><td>Charges & credits<sup>-4</sup></td><td>–</td><td>621</td><td>–</td><td>-238</td></tr><tr><td></td><td>$27,447</td><td>$5,156</td><td>$22,702</td><td>$3,934</td></tr></table>

Question: What is the average amount of Tradenames of 2010 Gross Book Value, and Drilling of 2009 Income before taxes ?
Answer: 1461.5
Reasoning program: add(1678.0,1245.0), divide(#0,const_2)