Plus - minus is how many points better the team are with or without you on the pitch.
So every time I play I’m worth +15 to my side.
Which is higher than any NBA or ABA player in history:
https://www.basketball-reference.com/leaders/bpm_career.html
Actually you're +15 per 100 possessions. BPM you're +17.4. Well, for that one season, but it's your only one so far. I assume those stats are total career stats.