This read-only PerfCounter64 reports the number of absolute round-trip jitter samples collected during the current measurement interval, per its description. An administrator uses this sample count as the denominator needed to convert the sum and sum-of-squares jitter objects into a statistically meaningful average and variance. For example, a monitoring tool would divide f3EsaProbeStatsSoamPmExtSumAbsRTJitter by this sample count to independently verify the reported average jitter figure.