Logging into the leaderboards gives you your percentile now, in 10% increments (will get to 1% increments as the data flows). I'm currently 90/90 for both PvP and achievements and not on either board... /wrists.
I would have thought that way less people played sPvP tbh. 90% percentile not being in the top 1000 means there are more than 10k qualifying players. Who knew.