Mainlanders appear to be perverse compared to most peoples around the world, and they have their media censors to blame. They seem to be more interested in stocks than sex, if Google China's search records are anything to go by. The names of three mainland banks, and the words 'stocks' and 'QQ', a Chinese-language instant message service, were more googled last year than 'sex'. The stocks of all three banks have been shooting up until recently. In most other countries, 'sex' beats all other word searches. The China Daily laments that mainlanders may have taken an unhealthy interest in money and technology over sex.
But that's probably not the case. The internet is heavily censored on the mainland, with the co-operation of western companies including Google. And pornography is the most heavily censored area. Mainland sex sites are being removed and access to overseas ones is blocked. This is probably the real reason 'sex' searches ranked so low.