<Table> Economy of Zambia <Tr> <Td_colspan="2"> Lusaka is the capital and largest financial district in Zambia </Td> </Tr> <Tr> <Th> Currency </Th> <Td> Zambian kwacha (ZMW) </Td> </Tr> <Tr> <Th> Fiscal year </Th> <Td> calendar year </Td> </Tr> <Tr> <Th> Trade organisations </Th> <Td> WTO, SADC, COMESA </Td> </Tr> <Tr> <Th_colspan="2"> Statistics </Th> </Tr> <Tr> <Th> GDP </Th> <Td> $379.65 billion (2015 est .) </Td> </Tr> <Tr> <Th> GDP rank </Th> <Td> 105th (nominal) / 120th (PPP) </Td> </Tr> <Tr> <Th> GDP growth </Th> <Td> 2.9% (2015), 3.8% (2016), 3.9% (2017e), 4.1% (2018f) </Td> </Tr> <Tr> <Th> GDP per capita </Th> <Td> $7,300 (2015) </Td> </Tr> <Tr> <Th> GDP by sector </Th> <Td> agriculture: 8.6%, industry: 31.3%, services: 60% (2015 est .) </Td> </Tr> <Tr> <Th> Inflation (CPI) </Th> <Td> 12.5% (2016) </Td> </Tr> <Tr> <Th> Population below poverty line </Th> <Td> 60.5% (2010) </Td> </Tr> <Tr> <Th> Labour force </Th> <Td> 6.906 million (2015) </Td> </Tr> <Tr> <Th> Labour force by occupation </Th> <Td> agriculture: 85%, industry: 7%, services: 9% (2004) </Td> </Tr> <Tr> <Th> Unemployment </Th> <Td> 13.3% (2014 est .) </Td> </Tr> <Tr> <Th> Main industries </Th> <Td> copper mining and processing, construction, foodstuffs, beverages, chemicals, textiles, fertilizer, horticulture </Td> </Tr> <Tr> <Th> Ease - of - doing - business rank </Th> <Td> 85th (2017) </Td> </Tr> <Tr> <Th_colspan="2"> External </Th> </Tr> <Tr> <Th> Exports </Th> <Td> $6.316 billion (2015 est) </Td> </Tr> <Tr> <Th> Export goods </Th> <Td> copper / cobalt 64%, cobalt, electricity; tobacco, flowers, cotton </Td> </Tr> <Tr> <Th> Main export partners </Th> <Td> China 25.5% DR Congo 13% South Africa 6.4% South Korea 4.9% India 4.3% (2015) </Td> </Tr> <Tr> <Th> Imports </Th> <Td> $6.798 billion (2015 est) </Td> </Tr> <Tr> <Th> Import goods </Th> <Td> machinery, transportation equipment, petroleum products, electricity, fertilizer; foodstuffs, clothing </Td> </Tr> <Tr> <Th> Main import partners </Th> <Td> South Africa 34.5% DR Congo 18.2% Kenya 9.7% China 7.2% India 4.4% (2015) </Td> </Tr> <Tr> <Th_colspan="2"> Public finances </Th> </Tr> <Tr> <Th> Public debt </Th> <Td> $6.73 billion (2014) </Td> </Tr> <Tr> <Th> Revenues </Th> <Td> $3.643 billion (2015) </Td> </Tr> <Tr> <Th> Expenses </Th> <Td> $5.189 billion (2015) </Td> </Tr> <Tr> <Th> Economic aid </Th> <Td> recipient: $640.6 million (2002) </Td> </Tr> <Tr> <Th> Credit rating </Th> <Td> B+ (Domestic) B+ (Foreign) B+ (T&C Assessment) (Standard & Poor's) </Td> </Tr> <Tr> <Td_colspan="2"> Main data source: CIA World Fact Book All values, unless otherwise stated, are in US dollars . </Td> </Tr> </Table> <Tr> <Td_colspan="2"> Lusaka is the capital and largest financial district in Zambia </Td> </Tr> <Tr> <Th> Currency </Th> <Td> Zambian kwacha (ZMW) </Td> </Tr>

Explain the effect of commercial banks on the zambias economy