Result type of AveragingCounter<int>::mean

The AveragingAccumulator has some disadvantages when used with integer types. I think constraining the return type of mean() to be the same as the underlying type is maybe not a good default as it forces the use of floating point types even if the underlying values are integers:

https://gitlab.cern.ch/gaudi/Gaudi/blob/master/GaudiKernel/GaudiKernel/Counters.h#L535-546

    /**
     * AveragingAccumulator. A AveragingAccumulator is an Accumulator able to compute an average
     * @see Gaudi::Accumulators for detailed documentation
     */
    template <typename Arithmetic, atomicity Atomicity = atomicity::full>
    struct AveragingAccumulator : AccumulatorSet<Arithmetic, Atomicity, CountAccumulator, SumAccumulator> {
      Arithmetic mean() const
      {
        auto n = this->nEntries();
        return n ? this->sum() / n : Arithmetic{};
      }
    };

I wonder if we should introduce an additional typename ResultType = double for mean(). Or could it be simply auto mean() const? The same would apply for all other Accumulators and their methods where divisions are involved.