Conversation so far:
What kind of oil is in North Dakota
The oil-rich Bakken shale formation has made North Dakota the second-largest crude-producing state behind only Texas.
Why has the oil-rich Bakken Shale formation made North Dakota the second largest crude -producing state in the U.S.
North Dakota generated 852 million barrels of Bakken crude, The Bakken and the Three Forks formation are 94% of Dakota's current oil production, with about 1 million barrels a day.
In how many U.S states do we find the production of crude oil.
Crude oil is produced in 32 U.S. states and in U.S. coastal waters.
Which U.S. states produce the most crued oil
The U.S. top five crude oil-producing states in 2018 were Texas with 40.5%, North Dakota with 11.5%, New Mexico with 6.3%, Oklahoma with 5.0%, and Alaska with 4.5%.

Question: When did the extraction start in the U.S.
Self-contained rewrite: When did the U.S. started extracting crude oil