How much of the US electricity generation is attributed to coal?

According to the US Energy Information Administration (EIA), in 2017, the United States generated about 4,015 billion kilowatt-hours of electricity at utility-scale facilities. About 62.7% of the electricity generated was from fossil fuel (coal, natural gas, and petroleum), with 30.1% attributed from coal.

See a complete breakdown of all energy sources from the US EIA.