Harvesting data is the norm in the modern age, so why not do that myself? Here's some data for you.
Nerds online right now:90702
OSRS Peak Online Player Tracker109,516 players - 20:54 on 16/02/2020
OSRS Lowest Online Player Tracker8,854 players - 11:32 on 27/02/2020
I have been tracking OSRS player count since16:15 on 28/01/2020