Average time before was six months to a year. Less around the early 1900’s - like four months.
In the infamous “Double Indemnity” murder case (the one on which the book was loosely based) the time between the crime and execution was less than a year. In the Saco and Vanzetti case, one or the defense’s last ditch efforts to evade an all too well deserved fate was to claim that the seven years that had lapsed between the crime and execution consistituted cruel and unusual punishment! (A delay entirely attributable to dubious pettifogging and spurious claims by the defense.) Today, even in Texas, an execution less than seven years after the crime would be speedy.