These sort of studies, as well as these sorts of questions are, for the most part, meaningless. To begin with these studies are just a small subset of US scientists - a small enough portion of all scientists to make any generalized statements invalid. In some of the studies, but not all, "God" is distinguished as a deity one can pray to and receive answers (in other words a personal God), yet scientists like Einstein (and many others) would confirm a belief in a God but not a personal God. These scientists might reject all religions yet retain a belief in some universal truth which they would call God (on a survey) but which would not satisfy very many religions. Other scientists would toss out studies that included social scientists as true scientists.

The trouble with all of these studies (and questions) is that the terms "God" and "scientist" mean too many things to too many people and can be interpreted in too many ways. You'll never find a good answer to your question and I wonder what it would mean anyway.