Recent evidence provided by the ECB shows that, over the period 1990-99, the 12 countries now comprising the euro area experienced a downward trend in the degree of inflation dispersion - measured as the standard deviation of that dispersion - from about 6 percentage points in the early 1990s to a low of less than one percentage point in the second half of 1999.
Since that time, inflation dispersion has changed very little - that is, it remains less than a percentage point. To provide a basis of comparison, since 1999 inflation dispersion across the euro area has fluctuated close to the level observed across the 14 metropolitan statistical areas of the United States.