When I book my first HDB flat, HDB officer told me I need to wait for 7 years in 1988 for my queue number to be call not including the building time.
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At the height of the property boom in the mid-90s, there were as many as 150,000 buyers in the queue, and the
wait for a flat was as long as seven years. However, when the Asian Financial Crisis struck in 1997, the queue vanished, virtually overnight. HDB ended up with 31,000 unsold flats, which took more than five years to clear. Because of the unintended oversupply, home buyers could walk in to buy ready flats in the early 2000s. However, home owners paid a heavy price, with flat prices staying depressed. Some who bought flats just before the crisis ended up with negative equity and even lost their homes and hard-earned savings. The many unsold flats represented a waste of taxpayers’ money. The holding cost incurred was money that could have been spent on healthcare, education, or other areas.
https://www.mnd.gov.sg/Reflections on Housing a Nation/Reflections on Housing a Nation.pdf