Russia’s gas output declined in the first half of the year as higher exports to China and increased domestic demand failed to make up for lost flows to Europe via Ukraine.The nation produced 334.8 billion of natural and associated gas through June, down 3.2% from the same period a year ago, according to Bloomberg calculations based on industrial output data from the nation’s Federal Statistics Service. Russia’s energy giant Gazprom PJSC accounts for nearly two thirds of Russia’s gas output.