Otousan ga Hayaku Shinimasu you ni
お父さんが早く死にますように。 · おとうさん が はやく しにます ように
est. Rough estimate based on volume count, reprints and magazine — not an official figure
Overview
Asuka and Hotaru are close sisters who seem to have a healthy family life from the outside even though they don't have a mother. Their dad, though, seems to "discipline" them quite often.
Source: AniList
External databases: AniList
How to compare editions, collected volumes and ISBNs / Sources, updates and corrections