I'd be willing to bet that 18 is actually a big fat 0 under construction. Plenty of projects half finished and planted with bunch grasses in bunkers and trees in the greens.
I just spent the month of December in China travelling all around the country and very little building construction going on, I think the dust has finally settled with the construction boom. Every city has a brand new airport, highways, and high speed rail lines linking just about every major city. Not much left to do.
It was as if they were playing Sim City in Sandbox mode for the past 20 years. Not anymore.