I consider myself pretty well informed, but still far from enough to evaluate that.
There are some obvious suspects, basically north and west Europe, Canada, USA, Australia and New Zealand. (Not sure about Japan and South Korea, don't really know enough to say even this much about them.)
Big question is how we interpret monarchy. Most of these are monarchies which could mean they can't win, but on the other hand the monarchies don't have real political effect. Yet again, that does mean there's no directly elected head of state and thus there's one less separate actor in the governance.
So if we exclude monarchies for that, we basically have France, Germany, Finland, Iceland, Ireland and USA to choose from. It'd take lot more research and analysis to pick one.
But effectively Nordic monarchies and couple more should still be in competition too.
Also it's hard to judge what is really the system by design and what is the current situation of politics (which in most of these cases tends to be worse than for decades...)