How many managers have the Mariners had?

Since their formation in 1977, the Seattle Mariners have had 11 managers. They are:

Darrell Johnson 1977-1980
Maury Wills 1981
Rene Lachemann 1981-1983
Del Crandall 1983-1984
Chuck Cottier 1984-1986
Marty Martinez 1986
Dick Williams 1986-1988
Jim Snyder 1988
Jim Lefebvre 1989-1991
Bill Plummer 1992
Lou Piniella 1993-present