PricewaterhouseCoopers - best known for competence with calculators rather than clairvoyance - is again in annual prophetic mode, conferring on a receptive world its best guess as to global adspend over the next five years.

According to PwC, world advertising expenditure will increase at a compounded annual growth rate of 6.2% to $521 billion (€414.5bn; £283.17bn) in 2010 - up from $385bn in 2005. The internet will remain the fastest-growing ad medium over that period, thanks in part to continued broadband penetration.

The study indicates that online advertising will grow at an annual rate of 18.1% to somewhere near $52bn in 2010 - by which year the web will account for almost 10% of global adspend compared with 5.8% in 2005. Online ad expenditure in 2005 was $12.5bn.

Data sourced from Wall Street Journal Online; additional content by WARC staff