Read the following texts and table with financial data from an S&P 500 earnings report carefully.Based on the question-answer history (if provided), answer the last question. The answer may require mathematical calculation based on the data provided.


devon energy corporation and subsidiaries notes to consolidated financial statements 2013 ( continued ) proved undeveloped reserves the following table presents the changes in devon 2019s total proved undeveloped reserves during 2014 ( in mmboe ) . . <table class='wikitable'><tr><td>1</td><td>-</td><td>u.s .</td><td>canada</td><td>total</td></tr><tr><td>2</td><td>proved undeveloped reserves as of december 31 2013</td><td>258</td><td>443</td><td>701</td></tr><tr><td>3</td><td>extensions and discoveries</td><td>153</td><td>8</td><td>161</td></tr><tr><td>4</td><td>revisions due to prices</td><td>-1 ( 1 )</td><td>-34 ( 34 )</td><td>-35 ( 35 )</td></tr><tr><td>5</td><td>revisions other than price</td><td>-61 ( 61 )</td><td>18</td><td>-43 ( 43 )</td></tr><tr><td>6</td><td>sale of reserves</td><td>-4 ( 4 )</td><td>-2 ( 2 )</td><td>-6 ( 6 )</td></tr><tr><td>7</td><td>conversion to proved developed reserves</td><td>-40 ( 40 )</td><td>-49 ( 49 )</td><td>-89 ( 89 )</td></tr><tr><td>8</td><td>proved undeveloped reserves as of december 31 2014</td><td>305</td><td>384</td><td>689</td></tr></table> at december 31 , 2014 , devon had 689 mmboe of proved undeveloped reserves . this represents a 2 percent decrease as compared to 2013 and represents 25 percent of total proved reserves . drilling and development activities increased devon 2019s proved undeveloped reserves 161 mmboe and resulted in the conversion of 89 mmboe , or 13 percent , of the 2013 proved undeveloped reserves to proved developed reserves . costs incurred related to the development and conversion of devon 2019s proved undeveloped reserves were approximately $ 1.0 billion for 2014 . additionally , revisions other than price decreased devon 2019s proved undeveloped reserves 43 mmboe primarily due to evaluations of certain u.s . onshore dry-gas areas , which devon does not expect to develop in the next five years . the largest revisions , which were approximately 69 mmboe , relate to the dry-gas areas in the barnett shale in north texas . a significant amount of devon 2019s proved undeveloped reserves at the end of 2014 related to its jackfish operations . at december 31 , 2014 and 2013 , devon 2019s jackfish proved undeveloped reserves were 384 mmboe and 441 mmboe , respectively . development schedules for the jackfish reserves are primarily controlled by the need to keep the processing plants at their 35000 barrel daily facility capacity . processing plant capacity is controlled by factors such as total steam processing capacity and steam-oil ratios . furthermore , development of these projects involves the up-front construction of steam injection/distribution and bitumen processing facilities . due to the large up-front capital investments and large reserves required to provide economic returns , the project conditions meet the specific circumstances requiring a period greater than 5 years for conversion to developed reserves . as a result , these reserves are classified as proved undeveloped for more than five years . currently , the development schedule for these reserves extends though the year 2031 . price revisions 2014 2013 reserves increased 9 mmboe primarily due to higher gas prices in the barnett shale and the anadarko basin , partially offset by higher bitumen prices , which result in lower after-royalty volumes , in canada . 2013 2013 reserves increased 94 mmboe primarily due to higher gas prices . of this increase , 43 mmboe related to the barnett shale and 19 mmboe related to the rocky mountain area . 2012 2013 reserves decreased 171 mmboe primarily due to lower gas prices . of this decrease , 100 mmboe related to the barnett shale and 25 mmboe related to the rocky mountain area. .
Question: what was the change in the proved undeveloped reserves from 2013 to 2014?
Answer: -12.0
Question: and how much does this change represent in relation to the proved undeveloped reserves in 2013, in percentage?

-0.01712