Read the thread, Pens fan. Some was data that was on the web 15 years ago, hard to find now. We may have compiled it manually and lost it. It can be researched again if anyone chooses. Again, it showed that the Caps went from a decent balance of PP/PK to very heavily on the PK most of the time (regular season, iirc) soon after Hunter/Limo incident/Donut incident. There have also been recent stats where, despite good possession and scoring, they have been middle of the pack in penalties drawn, or worse.
Another bit is the graph already posted about playoff advantages. Your Pens were the 2nd most favored team in PP differential for that period. Caps were the least favored.