Conversation so far:
What was Raymond Berry's first coaching job ?
After retiring from playing, Raymond Berry joined Tom Landry's Dallas Cowboys coaching staff as receivers coach.
What year did Raymond Berry join the Dallas Cowboys ?
Raymond Berry joined Tom Landry's Dallas Cowboys coaching staff as receivers coach in 1968.
How many years did Raymond Berry work for Frank Broyles?
Raymond Berry worked for Frank Boyles from 1970–1972.
How long did Ramond Berry stay with Don McCafferty ?
Raymond Berry stayed with Don McCafferty from 1973–1975.
For how long did Raymond Berry work with Forrest Gregg ?
Raymond Berry worked with Forrest Greg from 1976-1977.
Did Raymond Berry get another catching job after the New England Patriots ?
Raymond Berry left football and worked in real estate until the Patriots fired Ron Meyer in the middle of the 1984 season and hired Berry to replace him.

Question: How many years did he work for the Patriots ?
Self-contained rewrite: How many years did Raymond Berry work for the Patriots ?