A prize was given away every 15 seconds of the 15th Anniversary celebration, which ran from 1986-87.
Disneyland Guide: Summer (1975)
The Magic Kingdom on its twentieth anniversary.
Disneyland Guide: Summer (1970)
The Magic Kingdom on its fifteenth anniversary.
Walt Disney World Discover Guide (1986)
The resort in its fifteenth year.
Walt Disney World 15th Anniversary Welcome Brochure (1986)
Happy 15th Birthday!