Googling, I have been unable to find the methodology for this 2004-2005 survey. I think that's because this is market research where the full report is expensive.
The same outfit asks different questions every year, and if you look here, on the last page, the 2012 methodology is crypticly summarized:
http://www.scribd.com/doc/99090098/2...World-Factbook
For the more affluent countries, it appears to now to be an internet survey -- or maybe they are sampling everyone and excluding those who admit not to using the internet. For the less wealthy nations, there is an "SES exclusion." In other words, they don't interview villagers or slum dwellers.
So they seem to be comparing affluent urbanites in China and India with average income people in western nations.
Totally unclear, following links from the LA Times article, is whether the time estimates are for book reading, or all reading.