How many viewers will the rugby world cup get?

i live in new zealand, and we're hosting the rugby world cup next year and the country is going nuts about it, and i just read an article in the paper interviewing a new player for the NZ team (the All Blacks), saying " the All Blacks are the biggest sporting brand in the world and i couldnt p up the opportunity to play for them at the biggest sporting competition in the world, the world cup, in front of 4 billion viewers". it then went on about the estimated tv viewer ratings to be at 3--4 billion. Now new zealand is rugby mad, and i wont be surprised if most of the country watches, but on a worldwide scale is it very popular? 4 billion people would be almost the entire tv-owning population of the world, and twice that of michael jacksons funeral, 3 times princess Dianas, 40 times the superbowl, it just sounds a little unrealistic to me. anybody have any evidence?