All I could find was FIFA which said:
"Total broadcast hours: 71,867
Total territories reached: 214
Total in-home audience reach
(20+ consecutive minutes): 2.2 billion
Total in-home audience reach (1+ minute): 3.2 billion
Average global in-home audience per live match: 188.4 million
Highest global in-home average audience
(2010 FWC South Africa final): 530.9 million
2010 FWC South Africa final match
In-home audience reach
(20+ consecutive minutes): 619.7 million
2010 FWC South Africa final match
In-home audience reach (1+ minute): 909.6 million"
But, can you trust FIFA's numbers when they've admitted to exaggerating numbers and guessing?
http://www.independent.co.uk/sport/...on-tv-viewers-was-a-quarter-right-438302.html
"According to Initiative Sports Futures, independent analysts with no ties to Fifa, the figure for the 2006 final was 260 million in the 54 key markets it surveyed, accounting for 90 per cent of the world's TV households."
It could have about 300-400 million viewers.