They were all sent, but not yet delivered. How long ago did you send? If it's within the past few hours, you could still be delivering the emails.
Thanks Dory. That's what I thought, but the status for the email says Finished.
This email was scheduled to begin sending about 2 hours ago.
I agree with Dory, a big group like that I would bet that it is still sending some. Marketo will qualify all of the leads and then the flow will still be running in the background. Keep and eye on it and check to see if that number grows or stays the same.