Why does Dr Pepper seem to 'fizz up' on opening much more than other carbonated bottled drinks?

Can't find what I am looking for
so someone may get some clues from this:

I once worked with a fellow, Bruce Provost of the Provost Brothers,
a fantastic pair of Australian entertainers
who no longer perform, regrettably...

Bruce once worked in an aerated drinks factory.
He told me that different flavours
are charged with a different amount of gas (CO2)
which gives a different degree of acidity..
to satisfy the palate for each kind of drink.

My guess is that Dr Pepper (disgustingly syrupy for me)
has an inordinate amount of CO2 which would create lots of pressure
that would cause it 'to 'fizz up' on opening much more than other carbonated bottled drinks'

Go to it...
:-)
K