HarperCollins e-book sales now comprise 11% of its total revenue, the company has said following parent NewsCorp's latest results.
As has now become customary, figures for HarperCollins were not stripped out. There was no mention of the publisher either in NewsCorp's results for the year to 30th June 2011.
According to Publishers Marketplace, in a brief statement, it said it "ended the year with a profitable quarter and exceeded its plan for the year".
Children's had its second best ever year and e-books comprise 12% of total sales in the US across the last 12 months. However, it added for its most recent quarter, e-books comprised 19% of US sales and 11% of worldwide.
Within its publishing segment, which includes newspapers as well as HarperCollins, operating income surged 37.8% to $270m (£166.8m) for the quarter to 30th June 2011. Operating income for the year to 30th June was up from $467m (£288.5m) to $864m (£533.7m).
Turnover for the latest quarter was up from $2.1bn (£1.3bn) to $2.4bn (£1.5bn). Across the full year it increased from $8.5bn (£5.3bn) to $8.8bn (£5.4bn).