Query: How much of all of Greece's energy demand was supplied by DEI in 2009?
Context: Energy production in Greece is dominated by the Public Power Corporation (known mostly by its acronym ΔΕΗ, 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.