In this paper, the main focus lies on the informal economy and on work in the shadow. The most influential factors on the informal economy are tax policies and state regulation. The size of the informal economy was decreasing over the period 1999 to 2007, from 34.0% to 31.2% for 161 countries...

"Estimations of the size and development of the shadow economy for 145 countries, including developing, transition and highly developed OECD economies over the period 1999 to 2003 are presented. The average size of the shadow economy (as a percent of "official" GDP) in 2002/03 in 96 developing...