Online advertising spending in Europe remained its double-digit growth in 2007, according to the latest PricewaterhouseCoopers (PwC) data compiled by the Interactive Advertising Bureau Europe (IABEurope).

On average, Internet ad spending grew 40 percent in the 16 countries surveyed, while online ad spending in the US only increased by 26 percent during the same period.

Advertisers in Europe spent €11.19 billion ($15.3 billion) online last year, compared to only €7.21 billion ($9.1 billion) in 2006, research firm eMarketer reported.

According to the IABEurope, the United Kingdom, Germany and France made up two-thirds of all online ad spending in Europe.

In Europe, the average online advertising spending per person was €81 ($110) in 2007.

Advertisers in Norway spent at €133 ($183) per person, the highest in the region, followed by those in the UK at €121 ($166) and Denmark at €110 ($150). In U.S., advertisers spent €92 ($126) per person in 2007.

The IABEurope pointed out that advertisers in more mature markets are more willing to spend on Internet users.

"The development of the more mature markets in Europe is a sign that they are seeing increasing amounts of investment from a wider range of advertisers than ever before," according to Nicki Lynas, senior manager at PwC.

However, regarding online ad spending projections, Carat predicted that growth in Europe, North America and Asia Pacific would all slow in 2008 and 2009.

Moreover, eMarketer predicts that U.S. online ad spending growth will slow down to 22.7 percent this year and 15.8 percent next year.