Some have more than others. Certainly Spain recently has been less stable than before. Israel is always unstable. But you have variation. How much instability PR produces really depends on the nature of parties and fragmentation, which is a function both of the system but also of how fragmented society is. You can have a closed list PR system introduced to a very homogeneous society that will not fragment it all that much.
On September 23rd, 2016. See this statement in context.