API said the 7.7 million bpd was a 10.5 percent decline from July 2012. Domestic crude oil production, meanwhile, rose 17.4 percent from July 2012 to 7.5 million bpd. That marks the ninth consecutive month domestic oil production was more than the 7 million bpd mark and marked the highest output for any month in the last 22 years.
Oil and natural gas production in the United States is increasing thanks in part to new technologies used to access natural reserves trapped in underground shale formations. Texas and North Dakota are leading the nation in terms of oil production.
API said gasoline demand increased 2.2 percent in July compared to the same month last year, though demand for last month was the second lowest for the month in 13 years.
"The summer travel season brought greater demand for several fuel types last month than we've seen in recent years," API Chief Economist John Felmy said in a statement Thursday. "On the supply side, we produced more domestic crude last month than at any other point in the last 22 years."
API said total U.S. petroleum deliveries, a measure of demand, increased 1.7 percent year-on-year to 18.9 million bpd, the highest level for July in three years.