It doesn't matter where the number was pulled from. The point is this looks like Biden did it as part of his presidency and that is completely dishonest. If you tell me you're going to 100m in the first 100 days that means the number starts at 0 on your first day.
No. Having a 100 million people vaccinated in the U.S. does not start at 0. Then you would have 100 million+ people vaccinated. The projection was made off of the data at the time of the estimate, which lead them to feel 100 million was possible. What you want is accountability for which president was in office for every last person, which is not what he is promising.
If Biden said "I would bring the DOW to 30k", you wouldn't expect him to first bring it to zero, or to arbitrarily start wherever it left off with the last president.
“This team will help get … at least 100 million covid vaccine shots into the arms of the American people in the first 100 days,”
Perhaps it's interpretation but I read that as meaning the number starts at zero. Your example says "I would bring the DOW to 30k" which is different from what Biden said. He didn't say I will bring the vaccine to 100m he said I will get 100m people vaccinated in 100 days. While I can see how that could be interpreted the way you claim I also can and do read it the other way.
Either way I think at a minimum there should be attribution as 16.5m is a significant amount of people already vaccinated that the graph appears to give him credit for.