Islington-based publisher Quarto posted a 5% increase in full year adjusted pre-tax profit and upped its final dividend by nearly 10% as it battles against the decline of bookstore shelf space.Adjusted pre-tax profit rose to $12.1m for the year ended 31 December 2011 from $11.5m the year before. Revenue increased to $186.1m from $176.4m previously. Net debt increased 14% to $81.4m, which includes the cost of two acquisitions. Revenue at its publishing division was up 6% at $123.6m while digital revenues totalled $2.1m in the year compared to $0.42m before."Book publishing is a mature business facing significant change, and the trading background is generally subdued. Quarto has done a good job: wrestling with the challenges, adapting to changing circumstances, and executing measured responses," said chairman and chief executive officer Laurence Orbach. He added, "It is difficult to ignore the apocalyptic tone of many reports about the industry, and the evidence that it is facing profound challenges that must be addressed... We continue to redouble our efforts to make and sell good books."Despite a generally subdued trading background and ongoing challenges, the final dividend has been increased 9.6%, making a total dividend for the year of 7.9p compared to 7.5p in 2010. Quarto said its bank revolving credit facility successfully refinanced and it will announce the appointment of its new COO shortly.