Sacks Per 100 Pass Attempts

Unlike the funny Grindiness Per Nine Inning (G/9), I have started using a real statistic. In my extremely recent post analyzing QB that have recently gone to new teams, I started using sacks per 100 pass attempts (S/100) to help me analyze how offensive lines affect QBs on different. Now I admit this is nothing groundbreaking or earth shattering by any stretch of the imagination, but I still feel like this is a useful stat, especially when analyzing QBs who go to different teams. FootballOutsiders does something similar like this when they analyze offensive lines, but I'm applying this to individual QBs. Also, if a stat like this already exists, please tell me so I can delete this post. Thank You.