The ‘game player account creation date analysis’ tool, found on the main dashboard for any Roblox game shows estimates for the percentage of the game’s players that made their accounts on the given year. The data behind this is based on RTrack Falcon’s gamepass platform, so the data is also based on people who have purchased gamepasses in that game.
To use the graph, simply hover over a bar for the given year and you’ll see the percentage of the game’s all time players that RTrack Falcon estimates to have joined the platform in that given year. This is not weighted by play sessions or the time the person played the game.

Try it out for yourself on the Pro example game, Adopt Me:
https://v3.rtrack.live/index?id=920587237
Lead developer and founder at RTrack