Gas Metering And Compressor Stations At NAK Naftogaz Ukrainy, Ukraine's Principal Transit Route Of Russian Gas To The EU [Getty Images]

An employee looks at the monitors of a desktop computer in the control room of a gas metering and compressor station, operated by Ukrtransgaz, a unit of Ukraine's state energy company NAK Naftogaz Ukrainy in Uzhhorod, Ukraine, on Wednesday, May 21, 2014. Russia supplies about 30 percent of Europe's gas needs, with half of that transported through pipelines crossing Ukraine. Photographer: Vincent Mundy/Bloomberg via Getty Images

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