I would guess that the percentage of natural gas has increased since 2014 in PA.
Cheaper natural gas from fracking in PA has increased the use of that energy source and lowered the amount of coal being burned. The direct result is much cleaner air for everyone downwind.
Still 0.36 TWh out of more than 220 TWh is a very expensive drop in a bucket. I betcha these are about 0.36 most expensive TWh in the batch.