1. A system, comprising: at least one computing device for processing a stream of data events by performing a method comprising: providing a running statistical summary of the stream of data events, wherein the hybrid histogram includes a plurality of percentile ranges, a set of boundary values that separate the percentile ranges, and a count associated with each of the percentile ranges; identifying a percentile range from the plurality of percentile ranges into which a new data event value falls, and for incrementing the count associated with the identified percentile range; periodically recalculating the boundary values such that each percentile range includes a substantially similar number of associated counts; and analyzing the hybrid histogram.