Britney's "Circus," No. 1 last week, dipped from 30,000 to 8,100 this week -- a massive drop of 73 per cent. AC/DC's "Black Ice" took a similar blow, sinking from No. 3 to No. 8 with sales of 5,400, compared to 30,000 last week -- a drop of 74 per cent.

At the top, Nickelback's "Dark Horse" moved into No. 1 from No. 2, with sales falling 69 per cent from last week to just under 9,000 copies. - more on this story

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