Around 60 per cent of the properties built in this region were financed directly by developers, who demanded to be paid back over short periods, typically of just about 5 years.  

This almost entirely excluded low-income populations from joining the housing market as they would require longer periods to pay off debts - Hence, they were driven to build their own makeshift homes on the outskirts of properly urbanized neighborhoods and so expanding favelas. 

According to census data, the annual growth rate of the city's population residing in favelas slowed in the 1960s - largely because the growth of the city as a whole slowed, due to a decrease in migration compared to the 40s and 50s.