2019 Annual Manga Sales Ranking Announced by Oricon.

Related rankings are compiled here
Oricon Comic Ranking Summary

The top spot was taken by the completed series "Demon Slayer."
The TV anime that aired in 2019 received a tremendous response,
Additionally, this led to an increase in manga sales, making it a flagship series for Shueisha and Weekly Shonen Jump.
2019 was a breakthrough year for "Demon Slayer," establishing a significant foundation for subsequent movies and sequels.

2019 Annual Manga Sales Ranking

Ranking / Estimated number of copies sold / Title / Author

1 12,057,628 Demon Slayer Koyoharu Gotouge
2 10,134,232 ONE PIECE Eiichiro Oda
3 7,661,361　Kingdom Yasuhisa Hara
4 7,454,745　The Promised Neverland Kaiu Shirai, Posuka Demizu
5 5,895,000　The Quintessential Quintuplets Negi Haruba
6 5,047,574　My Hero Academia Kohei Horikoshi
7 4,704,234　Attack on Titan Hajime Isayama
8 4,514,838　Haikyuu!! Haruichi Furudate
9 4,096,492　Kaguya-sama: Love Is War Aka Akasaka
10 3,414,482　That Time I Got Reincarnated as a Slime Fuse, Taiki Kawakami, Mitz Vah