Like you mentioned, this can really developed in to a directory for health professionals in the US. If developed I can easily see a low XXXX figure for the domain, because whether economy is up or down, people keep spending money on health, food and a few other basic necessities.
Without development, I agree with Yo that you might be able to get say a low XX figure or my opinion if you push it a little more might even be able to extract a low XXX figure