The Islamic State has introduced fines for not knowing the Quran well enough, among other financial penalties. The cash strapped group is thought to have lost some 30% of its income stream over the past year.

Other penalties include duties for installing satellite dishes, tolls for truck drivers and exit permits to leave cities.

ISIS was making $80 million per month in mid-2015 and is making only $56 million per month today, according to the American analysis firm IHS. The group has lost 22% of its territory over the past two years and seen its subject population decrease from nine million to six million.

As a result of U.S. and coalition air strikes, ISIS oil production has dropped from 33,000 to 21,000 barrels a day.

“Islamic State is still a force in the region, but this drop in revenue is a significant figure and will increase the challenge for the group to run its territory in the long term” IHS senior analyst Ludovico Carlino told media.

For more information about the Islamic State and its attempts to create a Caliphate see Clarion Project’s Special Report: The Islamic State (ISIS, ISIL)