Trying to know how many rows I have from the different fleets in django

I'm working with a project that has 3 models.

• Devices: All the devices involved in the project.
• Fleets: Each device is in one fleet.
• Data: The data that the devices send.

Now I want to know how much data have come me today.

In my view I have this,

def dataPlots(request):
    today = datetime.date(2020, 5, 18)
    data = DevData.objects.filter(data_timestamp__date=today)
    data  = loads(serializers.serialize('json', data))

If I use len() I can now the total value. But how can I know how much data do I have for each fleet?

I have come to create this loop that would tell me for each device, but what I need is the value for each fleet and furthermore I think I am getting complicated.

data_dict = {}
for d in data:
    if d['fields']['dev_eui'] in data_dict:
        data_dict[d['fields']['dev_eui']] = data_dict[d['fields']['dev_eui']] + 1
    else:
        data_dict[d['fields']['dev_eui']] = 1

print(data_dict)

The models are:

class Fleet(models.Model):
    fleet_id = models.IntegerField(primary_key=True, unique=True)
    fleet_name = models.CharField(max_length=20, unique=True)

class Device(models.Model):
    dev_eui = models.CharField(max_length=16, primary_key=True, unique=True)
    dev_name = models.CharField(max_length=20, unique=True)

    fleet_id = models.ForeignKey(Fleet, on_delete=models.CASCADE)

    def __str__(self):
        return self.dev_eui

class DevData(models.Model):
    data_uuid = models.UUIDField(primary_key=True, default=uuid.uuid1, editable=False)
    data_timestamp = models.DateTimeField()
    data = models.FloatField()

    dev_eui = models.ForeignKey(Device, on_delete=models.CASCADE)

    def __str__(self):
        return self.dev_eui

Can somebody help me? I imagine that combining two models and some filter should suffice, but I don't know how to do it.