This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.
Q: Passage: Energy production in Greece is dominated by the Public Power Corporation (known mostly by its acronym , or in English DEI). In 2009 DEI supplied for 85.6% of all energy demand in Greece, while the number fell to 77.3% in 2010. Almost half (48%) of DEI's power output is generated using lignite, a drop from the 51.6% in 2009. Another 12% comes from Hydroelectric power plants and another 20% from natural gas. Between 2009 and 2010, independent companies' energy production increased by 56%, from 2,709 Gigawatt hour in 2009 to 4,232 GWh in 2010. Question: How much of all of Greece's energy demand was supplied by DEI in 2009?
A:
85.6%