Future Acreage Expirations If production is not established or we take no other action to extend the terms of the leases or concessions, undeveloped acreage will expire over the next three years as follows:
## Table 0 ##
Future deepwater Gulf of Mexico lease expirations are reported according to the original lease terms.
We are currently unsure of the impact of the Deepwater Moratorium or lack of permit activity on the expiration dates of these leases and if any extensions will be granted.
Drilling Activity The results of crude oil and natural gas wells drilled and completed for each of the last three years were as follows:
## Table 1 ##
(1) Includes successful exploratory wells drilled but not yet producing.
A productive well is an exploratory, development or extension well that is not a dry well.
A dry well (hole) is an exploratory, development, or extension well that proves to be incapable of producing either oil or gas in sufficient quantities to justify completion as an oil or gas well.
As defined in the rules and regulations of the SEC, an exploratory well is a well drilled to find a new field or to find a new reservoir in a field previously found to be productive of oil or gas in another reservoir.
A development well is part of a development project, which is defined as the means by which petroleum resources are brought to the status of economically producible.
The number of wells drilled refers to the number of wells completed at any time during the respective year, regardless of when drilling was initiated.
Completion refers to the installation of permanent equipment for production of oil or gas, or, in the case of a dry well, to reporting to the appropriate authority that the well has been abandoned.
In addition to the wells drilled and completed in 2010 included in the table above, at December 31, 2010, we were in the process of drilling or completing 245 gross (204.5 net) wells onshore US, 2 gross (0.6 net) exploratory wells in the deepwater Gulf of Mexico, 1 gross (0.4 net) development well offshore Equatorial Guinea, and 1 gross (0.4 net) exploratory well offshore Israel.
Domestic Marketing Activities Crude oil, natural gas, condensate and NGLs produced in the US are generally sold under short-term contracts at market-based prices adjusted for location and quality.
Crude oil and condensate are distributed through pipelines and by trucks to gatherers, transportation companies and refineries.
Noble Energy, Inc.  Notes to Consolidated Financial Statements 123 Leviathan-1 Deep In January 2012, we returned to the Leviathan-1 well and began drilling toward two deeper intervals in order to evaluate them for the existence of crude oil (Leviathan-1 Deep).
In May 2012, due to high well pressure and the mechanical limits of the wellbore design, we suspended drilling operations.
Although the well did not reach the planned objective, we are encouraged by the possibility of an active thermogenic (crude oil generating) hydrocarbon system at greater depths within the basin.
We are continuing our evaluation of Leviathan-1 Deep and will integrate the data from the Leviathan-1 Deep well into our model to update our analysis and design a drilling plan specifically to test the deep oil concept.
We have secured a rig with the capabilities necessary to reach the target objective and plan to begin drilling an exploratory well in fourth quarter of 2013.
Tanin 1 Tanin 1 is a 2011 natural gas discovery located in the Alon A block, offshore Israel.
We and our partners are currently reviewing alternatives for the development of reserves from this asset.
Dolphin 1 Dolphin 1 is a 2011 natural gas discovery located in the Hanna license, southwest of the Tamar gas field.
We and our partners are currently reviewing alternatives for the development of reserves from this asset.
Dalit Dalit is a 2009 natural gas discovery.
We and our partners are working on a development plan which would include tie-in to the Tamar platform and have submitted a development plan to the Israeli government.
Cyprus During the fourth quarter of 2011, we drilled a successful natural gas exploration well (A-1) in Block 12.
We submitted an appraisal plan to the Cyprus government during July 2012 and are reviewing locations for appraisal drilling activities.
Gunflint Gunflint (Mississippi Canyon Block 948) is a 2008 crude oil discovery.
In July 2012, we drilled a successful Gunflint appraisal well.
We plan to drill a second appraisal well targeting the south area of the reservoir during first quarter of 2013.
Front-end conceptual studies have been completed, and we are working toward sanctioning of a scalable development project in 2013.
We are currently targeting 2017 for production start-up utilizing a standalone facility.
If we choose to connect to an existing third-party host, the project could have an accelerated completion schedule.
Note 8.
Equity Method Investments Investments accounted for under the equity method consist primarily of the following: ?45% interest in Atlantic Methanol Production Company, LLC (AMPCO), which owns and operates a methanol plant and related facilities in Equatorial Guinea; ?28% interest in Alba Plant LLC (Alba Plant), which owns and operates a liquefied petroleum gas processing plant in Equatorial Guinea; and ?50% interest in CONE Gathering LLC (CONE), which owns and operates natural gas gathering facilities servicing our joint venture properties in the Marcellus Shale.
Equity method investments are included in other noncurrent assets in the consolidated balance sheets, and our share of earnings is reported as income from equity method investees in the consolidated statements of operations.
Our share of income taxes incurred directly by the equity method investees is reported in income from equity method investees and is not included in our income tax provision in our consolidated statements of operations.
At December 31, 2012, our retained earnings included $111 million related to the undistributed earnings of equity method investees.
The carrying value of our AMPCO investment was $10 million higher than the underlying net assets of the investee at December 31, 2012.
The difference is related to capitalized interest which is being amortized into earnings over the remaining useful life of the plant.
Equity method investments are as follows:
## Table 2 ##
WESTROCK COMPANY NOTES TO CONSOLIDATED FINANCIAL STATEMENTS — (Continued) 131 Note 20.
Stockholders’ Equity Capitalization Our capital stock consists solely of Common Stock.
Holders of our Common Stock are entitled to one vote per share.
Our amended and restated certificate of incorporation also authorizes preferred stock, of which no shares have been issued.
The terms and provisions of such shares will be determined by our board of directors upon any issuance of such shares in accordance with our certificate of incorporation.
Stock Repurchase Plan In July 2015, our board of directors authorized a repurchase program of up to 40.0 million shares of our Common Stock, representing approximately 15% of our outstanding Common Stock as of July 1, 2015.
The shares of our Common Stock may be repurchased over an indefinite period of time at the discretion of management.
In fiscal 2019, we repurchased approximately 2.1 million shares of our Common Stock for an aggregate cost of $88.6 million.
In fiscal 2018, we repurchased approximately 3.4 million shares of our Common Stock for an aggregate cost of $195.1 million.
In fiscal 2017, we repurchased approximately 1.8 million shares of our Common Stock for an aggregate cost of $93.0 million.
As of September 30, 2019, we had remaining authorization under the repurchase program authorized in July 2015 to purchase approximately 19.1 million shares of our Common Stock.
Note 21.
Share-Based Compensation Share-based Compensation Plans At our Annual Meeting of Stockholders held on February 2, 2016, our stockholders approved the WestRock Company 2016 Incentive Stock Plan.
The 2016 Incentive Stock Plan was amended and restated on February 2, 2018 (the “Amended and Restated 2016 Incentive Stock Plan”).
The Amended and Restated 2016 Incentive Stock Plan allows for the granting of options, restricted stock, SARs and restricted stock units to certain key employees and directors.
The table below shows the approximate number of shares: available for issuance, available for future grant, to be issued if restricted awards granted with a performance condition recorded at target achieve the maximum award, and if new grants pursuant to the plan are expected to be issued, each as adjusted as necessary for corporate actions (in millions).

<table><tr><td></td><td colspan="6">Year Ended December 31,</td></tr><tr><td></td><td colspan="2">2011</td><td colspan="2">2012</td><td colspan="2">2013</td></tr><tr><td></td><td>Gross</td><td>Net</td><td>Gross</td><td>Net</td><td>Gross</td><td>Net</td></tr><tr><td>(thousands of acres)</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Onshore US</td><td>177</td><td>140</td><td>215</td><td>142</td><td>978</td><td>740</td></tr><tr><td>Deepwater Gulf of Mexico</td><td>60</td><td>31</td><td>46</td><td>23</td><td>37</td><td>23</td></tr><tr><td>Equatorial Guinea</td><td>82</td><td>28</td><td>-</td><td>-</td><td>-</td><td>-</td></tr><tr><td>Suriname</td><td>1,080</td><td>486</td><td>2,007</td><td>903</td><td>-</td><td>-</td></tr><tr><td>Total</td><td>1,399</td><td>685</td><td>2,268</td><td>1,068</td><td>1,015</td><td>763</td></tr></table>
<table><tr><td></td><td colspan="3">Net Exploratory Wells</td><td colspan="3">Net Development Wells</td><td></td></tr><tr><td></td><td>Productive</td><td>Dry</td><td>Total</td><td>Productive</td><td>Dry</td><td>Total</td><td>Total</td></tr><tr><td>Year Ended December 31, 2010</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>United States</td><td>4.8</td><td>1.9</td><td>6.7</td><td>510.6</td><td>1.0</td><td>511.6</td><td>518.3</td></tr><tr><td>Equatorial Guinea</td><td>-</td><td>-</td><td>-</td><td>2.0</td><td>-</td><td>2.0</td><td>2.0</td></tr><tr><td>Israel-1</td><td>0.4</td><td>-</td><td>0.4</td><td>1.0</td><td>-</td><td>1.0</td><td>1.4</td></tr><tr><td>North Sea</td><td>-</td><td>-</td><td>-</td><td>0.6</td><td>-</td><td>0.6</td><td>0.6</td></tr><tr><td>China</td><td>-</td><td>-</td><td>-</td><td>2.3</td><td>-</td><td>2.3</td><td>2.3</td></tr><tr><td>Total</td><td>5.2</td><td>1.9</td><td>7.1</td><td>516.5</td><td>1.0</td><td>517.5</td><td>524.6</td></tr><tr><td>Year Ended December 31, 2009</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>United States-1</td><td>4.1</td><td>1.6</td><td>5.7</td><td>532.3</td><td>2.0</td><td>534.3</td><td>540.0</td></tr><tr><td>Equatorial Guinea-1</td><td>0.5</td><td>-</td><td>0.5</td><td>-</td><td>-</td><td>-</td><td>0.5</td></tr><tr><td>Israel-1</td><td>1.1</td><td>-</td><td>1.1</td><td>-</td><td>-</td><td>-</td><td>1.1</td></tr><tr><td>North Sea</td><td>-</td><td>-</td><td>-</td><td>1.0</td><td>-</td><td>1.0</td><td>1.0</td></tr><tr><td>China</td><td>-</td><td>-</td><td>-</td><td>0.6</td><td>-</td><td>0.6</td><td>0.6</td></tr><tr><td>Total</td><td>5.7</td><td>1.6</td><td>7.3</td><td>533.9</td><td>2.0</td><td>535.9</td><td>543.2</td></tr><tr><td>Year Ended December 31, 2008</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>United States-1</td><td>15.6</td><td>2.0</td><td>17.6</td><td>868.1</td><td>44.0</td><td>912.1</td><td>929.7</td></tr><tr><td>Equatorial Guinea-1</td><td>1.3</td><td>-</td><td>1.3</td><td>-</td><td>-</td><td>-</td><td>1.3</td></tr><tr><td>North Sea</td><td>-</td><td>0.4</td><td>0.4</td><td>0.6</td><td>0.3</td><td>0.9</td><td>1.3</td></tr><tr><td>Suriname</td><td>-</td><td>0.5</td><td>0.5</td><td>-</td><td>-</td><td>-</td><td>0.5</td></tr><tr><td>Total</td><td>16.9</td><td>2.9</td><td>19.8</td><td>868.7</td><td>44.3</td><td>913.0</td><td>932.8</td></tr></table>
<table><tr><td></td><td colspan="2">December 31,</td></tr><tr><td></td><td>2012</td><td>2011</td></tr><tr><td>(millions)</td><td></td><td></td></tr><tr><td>Equity Method Investments</td><td></td><td></td></tr><tr><td>AMPCO</td><td>$137</td><td>$147</td></tr><tr><td>Alba Plant</td><td>93</td><td>96</td></tr><tr><td>CONE</td><td>121</td><td>72</td></tr><tr><td>Other</td><td>16</td><td>14</td></tr><tr><td>Total Equity Method Investments</td><td>$367</td><td>$329</td></tr></table>

Question: What is the difference between the greatest Gross in 2012 and 2011？ (in thousand)