The original work, Grappler Baki, began back in 1991 and ran for 42 volumes through 1999 as done by Keisuki Itagaki.
That’s 110 volumes of the main series not including the spinoffs and side stories or the new series that populates it.
He then kicked off the next series in the property in 1999 with Baki: The Search of Our Strongest Hero, which ran until 2005 with a total of 31 volumes released.