Reuters Claims One Billion People Took Part in 'Earth Hour'

Reuters issued a dispatch this afternoon centering on a global effort to underscore the threat of global warming.  "World switches off to save planet in 'Earth Hour'" reports the news service.  The piece notes:
Lights went out at tourism landmarks and homes across the globe on Saturday for Earth Hour 2009, a global event designed to highlight the threat from climate change.

From the Sydney Opera House and Harbour Bridge to the Eiffel Tower in Paris and London's Houses of Parliament, lights were dimmed as part of a campaign to encourage people to cut energy use and curb greenhouse gas emissions from fossil fuels.

Organizers said the action showed millions of people wanted governments to work out a strong new U.N. deal to fight global warming by the end of 2009, even though the global economic crisis has raised worries about the costs.
Four paragraphs later appears "BILLION PEOPLE TAKE PART."  That isn't supported by what follows, which reports that the founding organization "is hoping one billion people from nearly 90 countries will take part."

So how does Reuters report that a billion people took part?  According to the International Energy Agency, "Some 1.6 billion people, about one quarter of the world’s population, have no access to electricity today." The CIA estimates the world's population at 6.7 billion, so that would mean about 5 billion people in the world could shut off their lights in the global feel-good exercise.  For Reuters to be correct in its one billion people claim, one out of five people would have had to participate.  Since Earth Hour hadn't even arrived for much of the world at the time Reuters released its report, how can the agency already state as fact that there were a billion participants?  

The obvious answer is it couldn't.  Reuters made up a nice, round number to buttress its contention of massive worldwide support for Earth Hour.  And no doubt it'll be picked up by mainstream media outlets across the country.