Zuido no Kuni no Kyuutei Majutsushi wa Annei wo Negau
瑞土の国の宮廷魔術師は安寧を願う · ずいど の くに の きゅうてい まじゅつし わ あんねい お ねがう
est. Rough estimate based on volume count, reprints and magazine — not an official figure
Overview
Note: Includes "Himitsu no Mori no Majutsushi wa Nodoka wo Negau: Bangai-hen (秘密の森の魔術師はのどかを願う 番外編)" and one extra chapter.
Source: AniList
External databases: AniList
How to compare editions, collected volumes and ISBNs / Sources, updates and corrections