U.S. energy security risks, which reached their highest level in 2011, dramatically improved over the next four years, and the nation’s burgeoning shale production had much to do with that upgrade, according to the U.S. Chamber of Commerce’s Institute for 21st Century Energy.

The risk index score fell to 77.9 in 2015, the lowest level since 1996, according to the 2016 edition of the group’s Index of US Energy Security Risk, which was released Thursday.

The index employs 37 different energy security metrics in four major areas of risk: geopolitical, economic, reliability, and environmental. A lower index score indicates a lower level of risk. Since 2011, the total risk index score has dropped by 25 points. Risk was down in 19 of the 37 metrics in the latest study, and increased in only five metrics.

“That this lowering of risk occurred at the same time U.S. energy companies were using hydraulic fracturing, horizontal drilling, and advanced seismic imaging to coax unprecedented volumes of oil and gas from shale formations is hardly a coincidence,” according to the report. “The beneficial effects of this energy revolution have rippled throughout the entire economy, lowering imports, improving our balance of trade, creating good-paying jobs, lowering energy prices and expenditures, and giving a still-ailing economy a much needed shot in the arm.”

Bowing to calls to make federal lands and offshore areas off limits to oil, natural gas and coal extraction would do significant economic damage, the report warns.

“Federal lands are the source of a significant, if declining, share of America’s energy production. We found that if policies restricting access to these federally-controlled resources were to be enacted, about one-fourth of all U.S. oil, natural gas, and coal production would be halted at a cost of $11 billion in lost royalties, 380,000 jobs, and $70 billion in annual GDP [gross domestic product].”

The impacts would be felt disproportionately in a few states, the researchers found. Wyoming would lose $900 million in annual royalty collections; New Mexico would lose $500 million; and five states — Colorado, Texas, Louisiana, Mississippi and Alabama would lose a combined 160,000 jobs.

Banning the still controversial hydraulic fracturing (fracking) would also be detrimental to the economy, the researchers said.

“We estimate that if a fracking ban were implemented, by 2022 natural gas, crude oil and wholesale electricity prices would increase by more than 400%. Many of the downstream industries that now rely on inexpensive natural gas would look elsewhere for supplies of feedstock and fuel, and some would close shop and move operations overseas.”