To use China as an example it has more than 50% Internet users compared to the United States yet StatCounter hits are 10 to 1 in favour of USA.
Because of language difficulties & government blocking of foreign sites most of China’s Internet traffic is probably internal.
http://www.bbc.co.uk/news/world-asia-pacific-14138267
A Chinese Internet user probably has a much smaller Global Internet presence than a US user.
Net Applications use the CIA Internet Traffic by Country table to weight their data do the CIA monitor Internal Chinese traffic accurately or are they more concerned with traffic flowing between China & the rest of the world.
probability is both StatCounter & Net Applications are not accurate