Its consistently higher that what the normal currency exchange rate would suggest in Asian countries.
For example if you multiply the USD rate of 1 BTC with the CNY rate, its 1 BTC = CNY 73,600, but exchanges there have it around CNY 75,500.
In other countries in Asia and South America also BTC is more expensive to buy in non-USD currencies than in USD.
Why is this the case?
Maybe it's because of the double conversion? You're using USD (naturally) to assess the value of BTC in CNY. Perhaps this leads to this difference? I think Yogee suggested a similar thought. I'd also like to see some proof that there's indeed a consistently visible difference. And if we're talking about local exchanges, their price of Bitcoin can include an additional fee, that accounts for making profit when someone buys or sells there. Then again, you were talking about a different type of exchanges, I believe... So there might be a real tendency due to the local market being somewhat isolated and Bitcoin being very actively used in Asia, but I think there's a bigger chance that this tendency is not real, but arises from some assessment mistakes.