For most of the Latin church's history after the early centuries, the diaconate survived only as a brief stage on the way to priesthood, a transitional deacon typically ordained mere months before ordination to the priesthood itself, so that a deacon who remained one was, in effect, a priest still in training. The Christian East never let the permanent diaconate lapse to the same degree, and Eastern Orthodox and Eastern Catholic churches have maintained ordained, non-celibate permanent deacons continuously.
The Second Vatican Council's restoration of the permanent diaconate in the West in 1967 changed the numbers substantially: married men can now be ordained permanent deacons in the Catholic Church, and their numbers, heavily concentrated in the United States, now run into the tens of thousands, filling roles in parish ministry that a declining number of priests cannot cover alone.
Protestant usage complicates any single picture of the office further. In Baptist and many congregational churches a deacon is not ordained clergy at all but an elected lay officer, often serving on a board that manages a congregation's temporal affairs and supports the pastor, a role with the same New Testament name as the Catholic or Orthodox order but a substantially different function and standing.