A report released by the Central Bank of Iraq indicates that the Islamic State militant group had stolen $830 million dollars from Iraqi bank facilities and reserves in 2014, according to Newsweek.

Following the terrorist organization’s caliphate declaration in July of 2014, the group has had a fairly large cash-flow. Their large income not only came from seized public and private banks, but also from the sale of oil and weapons, taxation, and human trafficking, among other things.

“Unlike many terrorist groups, which finance themselves mainly through wealthy donors, the Islamic State has used its control over a territory that is roughly the size of the U.K. and home to millions of people to develop diversified revenue channels that make it more resilient to U.S. offensives,” The Washington Post reported in 2015.

“Its main methods of generating money appear to be the sale of oil and antiquities, as well as taxation and extortion. And the group’s financial resources have grown quickly as it has captured more territory and resources.”

The extremist organization has become one of the wealthiest groups in history. At its peak, some analysts estimated that their annual income was somewhere around $3 billion.

But over the last two years, the group has been losing significant financial ground, having dropped from $1.9 billion in revenue in 2014 to about $870 million in 2016.

Reuters reported last year that due to significant losses in territory, ISIS was on the verge of complete collapse in revenue from oil smuggling, which is said to have brought in somewhere between $1 million to $2 million a day in 2014.

“[ISIS had] to cut fighters’ pay, levy new taxes, and raise fines for breaking its religious code,” according to Reuters. “[They had] to sell its remaining production at steep discounts to persuade truck drivers to collect it and run the gauntlet of US-led airstrikes.”

And their financial struggles solely persisted. Their expenses continued to include, but were not limited to, paying their militants (foreign fighters at some point were getting paid $1,000 a month), running schools and food kitchens.

Moving into 2017, ISIS revenue continues to plummet, as they get squeezed out by Iraqi and US led forces.

IHS Markit, a global data-monitoring company, released a report in late June that not only had the extremist organization lose 40% of their territory since the start of 2017, but that they were losing money from more than one area.

“The Islamic State’s average monthly revenue has fallen dramatically,” the statement reads. ” Average monthly oil revenue is down 88 percent, and income from taxation and confiscation has fallen by 79 percent, compared to our initial estimate in 2015.”

The company has predicted that ISIS revenue will not survive into its fourth year.