The Italian referendum in 1993, leading to a change to a Mixed Member Proportional System for the elections the following year, marked the beginning of a series of significant changes in electoral systems all over the world. In the vast majority of the cases, changes have been made on the margins, with a new seat allocation formula, a new number of electoral districts, or an extra few appointed members in the legislature; but many countries have also gone through reform processes that have altered their electoral system completely.

As Table 1 shows, the trend is rather clear. Most countries that have changed electoral systems have done so in the direction of more proportionality, either by adding a PR element to a plurality system (making it a Parallel or MMP system) or by completely replacing their old system with List PR. The most common switch has been from a plurality/majority system to a mixed system, and there is not one example of a change in the opposite direction. The new plurality/majority systems all come from within the same family except for the case of Madagascar, which moved from a List PR system, not to a pure plurality/majority system, but to a hybrid where the FPTP share is larger than the List PR share.