Since World War II, economies have exited currency unions at an average rate of one per year.

Andrew Rose found

…that countries leaving currency unions tend to be larger, richer, and more democratic; they also tend to experience somewhat higher inflation.

Most strikingly, there is remarkably little macroeconomic volatility around the time of currency union dissolutions, [emphasis added] and only a poor linkage between monetary and political independence.

Indeed, aggregate macroeconomic features of the economy do a poor job in predicting currency union exits.