Beijing - Almost one third of the world's population - a little over 2 billion people - watched the opening ceremony of the 2008 Beijing Olympic Games, according to the global market research company Nielsen on Thursday.

The number of viewers, though high, was less than the 4 billion China's state-run media had predicted.

The Nielsen Company said in a statement that it collected data from 38 key markets around the world, including host nation China, the United States, Brazil, South Africa, Italy and Australia.

Viewing level varied across regions and markets, impacted by factors such as time zone and broadcast time differences, the company said.

Comparing regions, the highest audience reach was in the Asia-Pacific, where more than five in 10 people watched the opening ceremony, followed by Europe, where 30 percent of the population watched, and North America, at 24 percent.

Looking at individual markets, the percentage of people tuning into the opening ceremony varied widely, the company said.

The four-hour long opening ceremony featured 29 sets of fireworks displays, as well as singers and dancers and special effects.

It was widely perceived as being spectacular, but controversy broke out later after a Chinese agency revealed that the little girl who in theory sang the Hymn to the Motherland during the ceremony, barely mimed. The voice that charmed the world belonged to a different girl who was not put on stage because she was not considered pretty enough.

The series of revelations about manipulations at the opening ceremony started a few days ago, when it became known that only one of the 29 fireworks footsteps seen on television during the show had actually happed on the opening day of the Games.

The other 28 were made and filmed around Beijing on previous days, when the sky was clearer than on the opening night of August 8 in which former gymnast Li Ning made his unforgettable "flight" around the inner upper ring at the National Stadium to light the Olympic flame. (dpa)