which stock market had the worst performance in the first half of 2011: Greece, Spain, Japan or Finland?

If you were to limit it to just the first half of 2011 then I would have to say Japan as the earthquake and tsunami were a completely unpredicted event.   The other countries are experiencing problems that have developed over a long period of time and to a certain extent had also been priced in over a long period of time.   They're certainly not doing well but their markets were just showing more of the same all along.