Mostly replaced implies >50% which is not the case. Gas is the most used fuel but has not 'mostly replaced' coal.

It's approx 50%, and it's more than any other.

1991 Coal 62% Gas 1.72% 2023 Coal 1.28% Gas 31.71%

So Coal dropped 60.72, Gas rose 30, oh no, it's slightly less than 50%, my point is invalid