The answer will vary depending on whether you are talking about gallons of air, gallons of water, gallons of salt, etc.
Depends on the type of engine.
The official statistics according to the EIA (Energy Information Administration) are that the US uses 9,253,000 barrels/day or 388.6 million gallons/day. Read more:...
13 million gallons of gasoline a day.....24-7
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