^ The construction itself is sustainable due to pre-sales volumes and a much more conservative development and financial industry following the market correction in the late 80s/early 90s.
If a building doesn't sell well it won't start construction.
The forecasts I've seen this year range from 12,000 - 14,000 sales (last year was approximately 17,000). More construction is likely this year however as many of last years sales will start construction this year (or have started the last few months).