Justin Houston had 22 sacks last year for the Chiefs, just one sack shy of breaking the modern NFL record. Houston did it while playing a full slate of games for the Chiefs, and Kansas City faced 591 pass attempts last year (including sacks). That means Houston recorded a sack on 3.7% of Kansas City’s opponent dropbacks.

That’s very good, although it’s just the 11th best rate since 1982. But we have to remember that sack rates have been steadily declining over the past few decades. For example, from 1982 to 2014, the average sack rate was 6.87%, but the 2014 rate was just 6.35%. In other words, we would need to increase the sack rate last year by 8.2% in order to adjust for era. So if we adjust for Houston’s 3.7% average by multiplying that average by 108.2%, his adjusted sack rate jumps to 4.03%. And that’s the second best rate since 1982.

Here’s how to read the full table. The top rate belongs to DeMarcus Ware, set when he was playing right outside linebacker for the Cowboys in 2008. That year, Ware played in 16 games, as did the Cowboys. Ware had 20 sacks that year and the Cowboys faced 567 opponent dropbacks. That means Ware sacked the opponent on 3.5% of pass plays. The league rate in 2008 was 5.9%, which means we need to adjust Ware’s average by 16.4%; that gives Ware an adjusted rate of 4.11%, the best since 1982.