devtrackers.gg
Wait is it actually that little? Out of so many players its only that little?
Any achievement that is added to any game post-launch will always have a weirdly low acquirement %. Percentages are out of everyone who has ever owned the game -- not active players at the time of its addition. For some games, that's out of tens of millions of players.
Technically all of the game's achievements were added a while after the initial EA launch onto Steam, but these curated map achievements in particular are especially recent. It's the same reason why Kuwait and Arid have rare achievements.