Greenland is big area wise but there are very few people living there.
You may have been to concerts or sports events that had more people in attendance than live in all of Greenland.
In addition to that it is not even fully its own country and any data collection would have gone to Denmark. Denmark is a small country area wise but it has a number of cities with more people in them than all of Greenland.
The Faroe Islands are in a similar position to Greenland in that they also are sort of semi independent but part of Denmark and also have a population about the same size.
You rarely see the Faroe Islands marked as having no data or having its data displayed on such maps though because most maps don’t even put them in and few people realize that they are missing.
The graph makers only mark Denmark with “no data” because it is so large and looks even larger on many common map projections, while treating similar populous anomalies as not even worth mentioning.
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