Actually a lot in NYC. Based on my experience when looking at houses before I bought mine gas lighting (unused) was ubiquitous.
The gas company tested the place for gas leaks (some sort of smell-o-vision meter) when I moved in. The real estate agent suggested I report smelling gas so the technician came out for free.
You don't have to be immediately beside the shower to achieve the objective.
I don't suggest everyone has the space but if you do, it's a lot better in the long term.