At the very minimum over three thousand Christians were killed for their faith in 2017 alone [1], although the true figure is probably far higher. The figures and the evidence for them were discussed in a report by an All-Party Parliamentary Group on International Freedom of Religion or Belief in the UK consisting of members of both the House of Commons and the House of Lords.
The report says that reported figures vary depending on how strictly you define a Christian, how you categorise the circumstances of their death, and how you count them.
Open Doors, a group that highlights persecution of Christians found that in the 12-month period ending October 2017, at least 3,066 Christians were killed for their faith.
Toward the middle of the scale, the International Institute for Religious Freedom, estimates between 4,000 and 6,000 Christians were killed for their faith in 2017. The institute argues that it often is difficult to determine with certainty whether a victim was a Christian, or if the killing was related to faith. As the aim is to estimate probable minimum and maximum numbers the numbers are somewhat larger than the bare minimum numbers of Open Doors.
At the high end of the scale, the Center for the Study of Global Christianity has estimated that 90,000 Christians were killed from mid-2016 to mid-2017 for religious motives. The figure is not based on an actual count but is declared “a calculated annual average over a 10-year period.” The number has its origins in an estimate for a ten-year period in the past that is averaged. The Center’s 2018 figure is a projection of that estimate into the present. The previous annual average over a 10-year period before 2010 was 100,000.