The National Bureau of Statistics has sharpened up its act in recent years, borrowing techniques from the International Monetary Fund, World Bank and US Department of Agriculture to improve data-gathering. But figures from cities and provinces still have an unknowable shuifen, or “water content,” as the euphemism has it. It is unlikely that a crack squad set up in 2006 to investigate manipulated data will, or can, catch all offenders.

That is why China-watchers have developed their own spectrum of integrity. At the good end are central bank statistics on lending, money supply and deposit growth, along with official trade and inflation numbers. All these can be verified and cross-referenced without much effort. At the other are figures on industrial production – too smooth, and too often at odds with energy consumption – and unemployment, which ignores men over 50, the recently laid off and many internal migrants.

Beijing, for its part, is showing a new candour, warning that the magical 8 per cent growth threshold may be beyond it this year. It may also recognise that presenting a flawless juggernaut is not in its own interests, especially if the evidence suggests otherwise. Uprisings, after all, can be more expensive than honesty. In 1990, after Tiananmen, growth fell to 3.8 per cent, less than half the 30-year average.