Saudi Arabia has one of the highest immigration populations on Earth, somewhere around 42% contrasted against 15.8% in the US (which is an all-time high). They offer huge wages for pretty much everything, have dirt cheap living costs, and like many Mideast countries - there's no taxes for individuals.
These are expats, not immigrants. They aren't welcome to become citizens in Saudi Arabia.
I'm not entirely clear that the migration dataset actually distinguishes between those cases?
My comment was based on Saudi Arabia's expat policy. Not on the dataset. Saudi Arabia doesn't welcome foreigners moving there to become citizens.