text: tackling undeclared work’ provides fact sheets of the type and quantity of undeclared work in all EU 
  Member States;464 Eurofound published several reports on platform work,465 and the FRA had a series 
  of publications and fact sheets on severe cases of exploitation, particularly of migrant workforces.466 
  Also, the creation of the European Labour Authority (ELA) 467 is partly a consequence of the**often**
  **irregular working conditions of mobile, posted, contracted or seasonal workers**who leave their 
  country to work in the EU or in another European country. ELA particularly aims to mitigate such critical 
  issues related to labour mobility and social security coordination between countries. 
  
  **In this report**, the quantitative data and the interpretation of the developments will cover — in an ideal 
  case —**the period 2005 to 2020**. In 2004, a major extension of the EU took place, from 15 to 25 
  Member States. If it is not possible to cover the whole period, the analysis is limited to the maximum 
  possible period. If comparability is high, for a very few selected data a further look back to the 1990s 
  was taken. 