Mechanisms are provided for determining an event rate. The mechanisms sample a sequence of events to generate a set of sampled events. At least a subset of the sampled events have associated event sequence values indicating a position of the sampled event within the sequence of events. The mechanisms group the sampled events into a plurality of event groups based on a common characteristic of the events. The mechanisms determine, for each event group, sequence values of sampled events associated with the event group. The mechanisms calculate, for each event group, an estimated event rate based on the sequence values of the sampled events associated with the event group and the total number of events in the sequence of events.