code: func (hg *Histogram) GetIncreaseFactor(totalCount int64) float64 {
  	columnCount := hg.TotalRowCount()
  	if columnCount == 0 {
  		// avoid dividing by 0
  		return 1.0
  	}
  	return float64(totalCount) / columnCount
  }
docs: // GetIncreaseFactor will return a factor of data increasing after the last analysis.