How many movies have Christopher J. Keene and David Zucker collaborated on?

They have worked on 4 movies together! Their first movie together was Ruthless People (1986) while their highest rated movie together was The Naked Gun: From the Files of Police Squad! (1988). They have not worked together since Naked Gun 33⅓: The Final Insult (1994). They are most known for their comedy films together.