grib/src/main/java/ucar/nc2/grib/grib1/tables/NcepTables.java
@Override
  public GribStatType getStatType(int timeRangeIndicator) {

    switch (timeRangeIndicator) {
      case 128:
      case 129:
      case 130:
      case 131:
      case 132:
      case 133:
      case 137:
      case 138:
      case 139:
      case 140:
        return GribStatType.Average;
      case 134:
        return GribStatType.RootMeanSquare;
      case 135:
      case 136:
        return GribStatType.StandardDeviation;
      default:
        return super.getStatType(timeRangeIndicator);
    }
  }
@Override
  public GribStatType getStatType(int timeRangeIndicator) {

    switch (timeRangeIndicator) {
      case 128:
      case 129:
      case 130:
      case 131:
      case 132:
      case 133:
      case 137:
      case 138:
      case 139:
      case 140:
        return GribStatType.Average;
      case 134:
        return GribStatType.RootMeanSquare;
      case 135:
      case 136:
        return GribStatType.StandardDeviation;
      default:
        return super.getStatType(timeRangeIndicator);
    }
  }
http://www.nco.ncep.noaa.gov/pmb/docs/on388/table5.html