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Considering the development of the shadow economy of 36 European and OECD countries over the period from 2003 to 2022 and the effect of the Coronavirus pandemic from 2020 onwards, the average size of the shadow economy of 36 European and OECD countries decreased from 16.48% of GDP in 2020 to 16.07% in 2021 (a decline of 0.41 percentage points). Due to a continued (forecasted) economic recovery in 2022, the average shadow economy of these 36 countries will slightly increase to 15.96% of GDP (average of all 36 countries): a very modest reduction of 0.11 percentage points.
Friedrich Schneider (Sun,) studied this question.