With the all the SPARQ work that Zach Whitman does, I thought it would be interesting to go through his database to find which position groups are producing the greatest number of NFL athletes (relative to their position -- the 0.0 Sigma is relative to the NFL Average for the position, not for their draft class) on both a percentage and absolute basis.
Zach has whopping 1,991 names in his 2015 database (over 2,000 with specialists), 1,004 on Defense and 987 on Offense. Of those 1,991 names, only 338 (17%) have SPARQ sigma scores that are 0.