Book publisher Bloomsbury posted a drop in annual pre-tax profit but raised its dividend and said trading in 2010 had been excellent, helped by bestsellers such as Ben McIntyre's Operation Mincemeat.Pre-tax profit fell to £7.1m for the year ended 31 December 2009 compared to £11.6m the year before. Revenue for the year fell to £87.2m from £99.9m previously.Chief executive Nigel Newton said, "This is a strong set of results, ahead of consensus market forecasts achieved under difficult trading conditions."Results were also against strong comparatives the previous year with the publication of 'Harry Potter and the Deathly Hallows' and The Tales of Beedle the Bard' in 2008.On an upbeat note, the group said trading has been excellent in the first quarter of 2010 with a range of new publications. Bloomsbury said it has a strong pipeline of releases for 2010 including the launch of a newly designed edition of Harry Potter on 1 November.Bloomsbury are recommending a final dividend of 3.65p, up from 3.47p the year before.