Answer:
There are no written records of underground activities.
Explanation:
There are different acts and jobs that make up for underground economy. It is primarily referred to as money earned from illicit activities like prostitution and the sale of illegal drugs. But it also broadly refers to any unreported income, such as undeclared tips or gambling winnings, or under-the-table payments made to laborers like house painters and construction workers, whose wages may go unreported to tax authorities. Unreported income paid to illegal aliens or migrant workers also contributes to the underground economy.
The underground economy also causes billions of dollars in lost taxes.
The Underground Economy and GDP
Due to its cloaked nature, it's difficult to gauge the true extent of the money that changes hands through the underground economy (sometimes referred to as the shadow economy).