Here Oricon Manga sales from November 20, 2017 to May 20, 2018.
Top 10 Best Selling Manga Series First Half 2018
1 - One Piece (3,110,049 copies).
2 - Shingeki no Kyojin (2,997,049 copies).
3 - Nanatsu no Taizai (2,769,915 copies).
4 - Haikyû!! (2,523,071 copies).
5 - Boku no Hero Academia (2,516,768 copies).
6 - Kingdom (2,516,063 copies).
7 - Black Clover (2,033,277 copies).
8 - The Promised Neverland (1,970,504 copies).
9 - Tokyo Ghoul:re (1,962,722 copies).
10 - One Punch-Man (1,658,054 copies).
Top 10 Best Selling Manga Volumes First Half 2018
1 - One Piece 88 (2,283,589 copies).
3 - Shingeki no Kyojin 24 (1,376,248 copies).
3 - Shingeki no Kyojin 25 (1,111,591 copies).
4 - Hunter x Hunter 35 (981,833 copies).
5 - Kingdom 49 (806,986 copies).
6 - Kingdom 50 (742,295 copies).
7 - Haikyû!! 29 (730,459 copies).
8 - Tokyo Ghoul:re 14 (714,734 copies).
9 - One Punch-Man 15 (704,860 copies).
10 - Haikyû!! 30 (694,489 copies).
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27 - One Piece 87 (401,245 copies).
Last year sales: http://www.arlongpark.net/showthread.php?t=45185