One of the greatest topless scenes in history.

I’ve pointed out before that the 1982-83 period may have been the Golden Age of screen nudity, and almost certainly was the Golden Age of nudity in the youthploitation genre. It would be difficult to choose the nude scene of the year in those years.
Some top options:
1982
Morgan Fairchild in The Seduction (1982)
Barbara Carrera in I, the Jury (1982)
Barbara Hershey in The Entity (1982)
Pia Zadora in Butterfly (1982)
Nastassia Kinski in Cat People (1982)
Mariel Hemingway and others in Personal Best (1982)
Phoebe Cates in Fast Times at Ridgemont High (1982)
Phoebe Cates in Paradise (1982)
Diane Franklin in The Last American Virgin (1982)
1983
Leah Thompson in All the Right Moves (1983)
Rebecca De Mornay in Risky Business (1983)
Virginia Madsen in Class (1983)
Caren Kaye in My Tutor (1983)
Betsy Russell in Private School (1983)
Pia Zadora in The Lonely Lady (1983)
Theresa Russell in Eureka (1983)
Catherine Deneuve and Susan Sarandon in The Hunger (1983)
Mariel Hemingway in Star 80 (1983)
Jamie Lee Curtis in Trading Places (1983)
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I think I would vote for Leah Thompson in 1983.
1982 is an impossible choice: I think Kinski and the two Cates scenes would be my top three, but I’m not sure of the order. Fast Times is the least impressive in terms of nudity, but is impossible to ignore because it is just so memorable.