The following graph shows all horizontal agreements which have been fined by the European Commission between 2000 and 2014 as well as corresponding follow-on claims by European country:
I collected the data on the cartel proceedings from the press releases of the European Commission. Via a google search corresponding follow-on claims were matched. Due to the nature of such a search, the data on follow-on claims should be treated as indicative only.
The data shows that more follow-on claims have been lodged in the middle of the period compared to the early and later periods. In this period we also see a particularly high number of cases which were pursued in several countries. However, the more recent the period, the less accurately the data likely reflects the actual picture, as information on claims might not yet have surfaced or claims are still in preparation.
The data also show, that the UK, the Netherlands and Germany are the preferred jurisdiction to file a suit.
Finally, the larger the fine, the more likely a follow-on-claim will be lodged.