I am interested in finding out the size of the informal economy in Nigeria for a ten year period. Official data sources are no help in this regard as this portion of the economy is rarely ever mentioned.
According to wikipedia Nigeria is middle income, mixed economy ranked 30th in the world in terms of GDP (PPP) as of 2011, wikipedia opines that this portion of the economy is near equivalent to 75% of the current economic size though with no relevant citations.
Another google search brought up an interesting dated (2002) research work by Friedrich Schneider, he opines that in the year 1999/2000 the informal economy of Nigera was 57.9% of the total economy which is equivalent to USD 212.6 billion and his estimates where based on his calculation using World Bank Data.
I moved on to search on World Bank sites to see if it reveals anything and it apppears all world bank sources seem to all so cite Friedrich Schneider works and so I moved back to focus more on his works.
So may be now one thing that is unique about my country is that there is a clear lack of data work with as regard the informal economy
With more focus now on Friedrich Schneider work's it apears that the attempts at capturing the size of the informal economy is usually based on models and not based on any form of direct measurement also it appears to lack of trending data for Nigeria's informal economy size.