 However, these efforts were not successful enough then in convincing the people living in the squatter settlements to move into these flats.It was after 25 May 1961, the day of the Bukit Ho Swee fire, that HDB's efficiency and earnestness won the people over.The HDB estimated that from 1959 to 1969, an average of 147,000 housing units—80,000 from the current deficit, 20,000 due to the redevelopment of the Central Area, and 47,000 due to population increase—would need to be constructed; an average of about 14,000 a year.