public long getMean() {
      long count = this.count.sum();
      long total = this.total.sum();
      if (count == 0) {
        return 0;
      }
      return total / count;
    }
Computes the quantiles give the ratios.
hbase-metrics/src/main/java/org/apache/hadoop/hbase/metrics/impl/FastLongHistogram.java