Pedantry
Pink Floyd, "Another Brick in the Wall, pt.3" was number from for 5 weeks starting in mid December 1979, so, it was number one for 3 weeks in 1980.

Not that Wikipedia's ever wrong, but, I'm just sayin'...
(Haviland drinking like they're going to ban beer., Sun 9 Nov 2008, 16:10, Reply)