Here is a breakdown of the cameras used by photojournalists in the 2018 World Press Photo contest (Nikon D5 and D810 at the top two spots, the photo of the year is taken with a Nikon D4s):
Breakdown by brand (Nikon: 51.5%, Canon: 29.9%, Fuji: 6.2%, Sony: 5.1% ):
Breakdown by camera system (DSLR: 83.5%, mirrorless: 11.3%):
Via Photolari