From the brevity file ...
"A growing number of ..."
How often do we read or hear that? But about half the time it's not needed.
A growing number of states are embracing the Medicaid changes. = More states are embracing ... (Or, if you want to emphasize the fluid nature, go ahead and use "more and more." It still saves a word.)

There can be a use for "a growing number": The program adds Tennessee to a growing number of states that are ..., for instance. (And vary it occasionally with more and more. Why always dip into the same bag of journalese?)