I'd be willing to bet this genius maneuver drives it back up.
Yeah, looking more closely at that graph, I'm noticing it starts in 2009, when Greece had The Crisis: sovereign debt soared thanks to the housing bubble collapse, and people taking a closer look at the actual books of the Greek state. Austerity measures are what led to the massive unemployment spike, and this 6-day work week is another version of austerity.
Austerity doesn't work. This graph couldn't be clearer about that fact.