You read correctly, on May 13, with the release of the twentieth volume, which suffered a delay due to the Coronavirus, Demon Slayer it will reach 60 million copies in circulation worldwide. This exorbitant number counts both digital units and the 2.8 million of the next volume out.
If we think that more or less a year ago, in April 2019 the manga had only 3.5 million copies circulating around the world, we can see that it had one growth about 17 times. After the anime aired, the popularity of the series grew vertiginously, so as to become the second best-selling manga in 2019 immediately below one piece.
On October 4, with the publication of the seventeenth volume, the work counted in total 12 million copies. The eighteenth volume debuted with one record edition of 1 million copies, bringing in the total number of volumes to more than 25 million. Only with the publication of the next issue, the 19th, the total copies are almost doubled (between paper and digital) touching share 40 million. This volume sold in the first week 1 million and 378 units, ranking first in the ranking of Oricon from 3 to 9 February, becoming the third manga in history to sell more than 1 million copies of a single volume in the first week after One Piece and The attack of the Giants.
April 27 Weekly Shonen Jump has announced that the series will reach its "climax" with the 204 chapter of Demon Slayer which will be released on 11 May on the twenty-third volume of the magazine. Chapter that will anticipate the final one, the 205, scheduled for May 18.
Recall that most likely Demon Slayer will count 23 volumes in all.
What do you think of the climb undertaken by the manga of Koyoharu Gotouge on the ending?