In the event of a 30-day GPS outage, the United States could face up to $35 billion in economic losses, and that number could increase to $45 billion during prime planting seasons for farmers, according to a report written by RTI International and sponsored by the National Institute of Standards of Technology.

The report, the “Economic Benefits of the Global Positioning System (GPS),” estimates the potential impact of a GPS outage over a 30-day period, as specified by the Department of Commerce. The report focuses on 10 industries: electricity, finance, location-bases services, mining, maritime, oil and gas, surveying, telecommunications, telematics, and agriculture.

Government officials have warned of threats to GPS and how a successful attack on that technology would impact national security. Those threats include the ability of adversaries to jam or spoof radio frequency signals, disrupting military operations.

“Hundreds of millions of users rely on GPS every day from people driving to some place new to multinational corporations coordinating complex logistical networks,” Alan O’Connor, director of innovation economics at RTI, said in a news release.

While the $45 billion number is possible if the outage occurs during critical agricultural planting seasons, a 30-day outage outside of those seasons could see $16-35 billion in economic losses.

GPS is used in agriculture for soil mapping as well as tractor and combine guidance.

The report says experts agree a 30-day outage would be “devastating.” On average, the report estimates a 17 percent revenue loss across corn, soybeans, wheat, rice, peanuts and cotton, with a margin of error of 6 percent.

The maritime sector would also face losses, which the report estimates at more than $10 billion. The steepest loses would come from June to September, according to the report’s analysis for 2016 catch revenues.

The hardest hit ports would be Los Angeles and Long Beach in California, which would face more than $2.2 billion and $1.9 billion in losses respectively. In total, port losses would total more than $6 billion.

The report estimates that since 2010, a average $1.3 billion per year (in 2017 dollars) has gone toward the research and development of GPS technology used for defense and civilian purposes.

The report says the impact on Day 1 would differ from that on Day 10. However, an outage would produce an average loss of $1 billion a day, before counting for agriculture.

The report does not place blame for the hypothetical outage, and the RTI news release notes that GPS outages to date have lasted less than one day.