I don't know the answer, but someone may have calculated those numbers. Suffice it to say that there were hundreds of Alabama men at Rock Island.

Of the men of the 38th Alabama, for example, 42 were never able to leave and lie there today: http://38thalabama.com/rock-island.html

https://www.nps.gov/nr/travel/national_cemeteries/Illinois/Rock_Island_Confederate_Cemetery.html