A system, method and program product for processing a stream of data events using scaled exponential smoothing for maintaining a histogram. A system is provided having: a set of histogram data that maintains a running value for each of a plurality of buckets; a bucket identification system for identifying a bucket b into which a new data event value belongs; an exponential smoothing system that applies a decay factor to the set of histogram data utilizing a first algorithm for the running value associated with bucket b, and a second algorithm for each remaining running value; and an analysis system for analyzing data event values in view of the histogram data.