Schneider, F., &Enste, D. H. (2000). Shadow economies: size, causes, and consequences. Journal of economic literature, 38(1), 77-114.
Using various methods, the size of the shadow economy in 76 developing, transition, and OECD countries is estimated. Average size varies from 12 percent of GDP for OECD countries, to 23 percent for transition countries and 39 percent for developing countries. Increasing taxation and social security contributions combined with rising state regulations are driving forces for the increase of the shadow economy, especially in OECD ...