In the U.S., we use about 18 million barrels of oil daily for all transport combined—which adds up to 756 million gallons per year. And that's just over a fifth of global demand for
Of that, about half goes to pump gasoline; that's settled downward, somewhat, from our peak use of 374 million gallons per day in 2006. The rest goes to what the government terms other refined petroleum products—like jet fuel, diesel, and toward products like motor oil.
Nearly every car on the road—unless it's an electric car—requires motor oil, and regular oil changes. Whether you use regular oil or the synthetic stuff, you're using ingredients and additives that are derived from crude oil. With each car on the road using on the order of five quarts (1.25 gallons) of motor oil at a time, and about 255 million passenger vehicles registered in the U.S., that adds up to hundreds of millions of gallons of motor oil.
That said, each car doesn't use motor oil in the way that it uses gasoline. The petroleum and auto-service industries are able to recover and recycle the vast majority of used motor oil, cleaning and repurposing some for commercial or industrial uses (like power plants), or using it to create new petroleum-based products.
Modern cars do typically use some oil between oil changes, but it varies depending on the model and the age and wear of the vehicle. Keep in mind that oil can leak as you're driving, or onto your driveway or garage floor, so look for those signs; and if you're using noticeable amounts of oil and not noticing leaks, your engine is burning it.
Especially as maintenance and oil-change intervals have gotten longer, with many newer cars, it's not unusual to add a quart between visits to the dealership or your mechanic. Even a quart every 1,500 miles in a high-performance car or in extreme conditions like towing is not all that unusual.
Check in your owner's manual for what could be considered normal for your model, and ask your mechanic. And of course, don't forget to check your oil regularly.