Around Germany and Greece there were other countries. They went by names like frugal four and PIIGS. They forced "austerity" and stricter working hours onto indebted countries to save their own banks.
The colours on this map show well that northern "productivity" is not about working hours, but about other topics that did not get addressed. Among these topics are also tax heavens (think the Netherlands) and money laundering (think Austria's special relationship with Russia).
So it was nothing more than poor political leadership without vision.
It's opposed to when one party stays at home full time to take care of the children, it's not counted, and doesn't detract from average work hours of the people that have work.
It's probably similar in other countries, but here (Denmark) the norm is that women work full time just as much as men, and this has been the case for decades. Also our unemployment rate has for years hovered around the theoretical minimum.
The retirement age has been increased, and is now about 70 years, and for younger generations it is set at 74!! IMO that's too high, and I don't believe the argument that it is necessary. But that's what our government has done.
So as a population I'm pretty sure we probably have reasonably high average rate of work hours per capita.