Briefly define the informal economy and discuss how the implementation of the structural adjustment programs in sub-Saharan Africa has spurred its growth?

an informal economy is defined as all aspects of the economy that take place outside official channels or "off the books". informal economies provide alternative sources of income and stability. In an informal economy work is often bartered for food, housing, services, or for cash, all payments that are not reported to the government as taxable income. However this may also lead to sex-work, smuggling, the drug trade, selling endangered animals, and other dangerous events.

I need help explaining how the the implementation of the structural adjustment programs in sub-Saharan Africa has spurred its growth