That's actually an interesting question, and I don't think we have the data to answer it. But we do have the Steam data, and about 7% of Steam users have a GPU that can run it well at a 4-Bit quant (≥24 GB VRAM). About 30% can run a 3-bit quant - I'd say that's just barely usable (≥16 GB VRAM).

I'm not sure whether that's low or high, or how it compares to a general audience.