I developed Special Teams Efficiency last year after realizing that total special teams percentage would always average 100% league-wide. As I said in the original article:

If we had a simple metric to apply to special teams, we could get a sense of just how much of an impact special teams can have on a season. Since the league average for power play success percentage plus penalty kill success percentage is 100, why not add the two and use it as a baseline for measuring special teams efficiency? Though the tendency to regress toward the mean may be somewhat less strong (but then again, maybe not!), it may still be useful as an evaluation tool. In this case, we'll call the combined number Special Teams Efficiency, or STE. Since the post-lockout orgy of power plays (2005-2007) the per team yearly average of special teams situations is 643. If all teams were to draw the same amount of penalties, a team with a 100 STE would net zero special teams goals. It follows, then, that a team with a 105 STE would net 32 special teams goals more than average, and a team with a 95 STE would net 32 special teams goals less than average.

The Oilers were far and away the worst team in the league at the time, so bad in fact, the Oilers were twice as worse as any other team in the league except two, the Panthers and Maple Leafs:

The Oilers' special teams are so bad that if they were to continue on their current pace, they would net -110 goals by the end of the season compared to an average team. They would net -190 goals compared to the Canucks.

I've listed the December STE and goal differential next to the final STE and final goal differential in the table below: