Who the heck knows? There has been quite a bit of speculation here and elsewhere. I think I've found a reference that adds real value to the conversation. This diary is an extension of a comment found here.
From Lenz blog, I find a pdf (auf Deutsch) that appears to be quite useful in answering the question. The source is, according to Lenz:
Arbeitsgemeinschaft Energiebilanzen, a leading German organization for statistic data on energy.It should also be noted that these data are "Vorläufige Angaben, z.T. geschätzt" which, I believe means something akin to "preliminary data, some values are estimates".
Results below the Kos Doodle.