Approximately 90,000 Christians were killed for their faith in 2016 worldwide, making them the most persecuted religious group in the world. That number — which amounts to one Christian killed every six minutes — is down a bit from 2015 when the number was estimated to be approximately 105,000

According to a Fox News report, nearly a third of the deaths in 2016 were at the hands of Islamic extremists like ISIS, and others were killed by state and non-state persecution. Massimo Introvigne, director of CENSUR, told Vatican Radio that approximately 70 percent of the martyred Christians in 2016 were from tribal villages in Africa, and their deaths were partially a result of the fact that Christians often refuse to take up arms during conflicts.

The Center for the Study of Global Christianity also studies Christian martyrdom, both historical and contemporary, and estimates that between 2005 and 2015 there were 900,000 Christian martyrs worldwide—which comes out to an average of 90,000 per year. The Center says historical, sociological, and theological arguments in quantifying Christian martyrdom throughout time must be considered. Their definition of a Christian martyr is: “Believers in Christ who have lost their lives prematurely, in situations of witness, as a result of human hostility.”

The number of Christians martyred in 2016 is likely more than 90,000, however, because studies were not able to include data from China and India — two countries with large Christian populations, but with “underground” churches, so the numbers of persecuted and martyred Christians are hard to come by.