Between 3.9 million and 4.8 million unauthorised immigrants lived in Europe in 2017, mainly recently arrived young men, numbers slightly lower from the previous year, the US-based Pew Research Center said Wednesday.
The figures “accounted for less than one percent of Europe’s total population of more than 500 million,” Pew said.
For the study, an unauthorised migrant was defined as a foreigners who entered the country illegally, those whose residence permit has expired, are under expulsion orders, or asylum seekers with pending decisions, Pew said.
Pew analysed data from the European Union and European Free Trade Association countries (Switzerland, Liechtenstein, Norway and Iceland).
The US researchers said the number of unauthorised migrants in Europe peaked in 2016 at between 4.1 and 5.3 million.
In 2017, 30 percent of the migrants were from the Asia-Pacific region, including Afghanistan.
The next largest group -- 23 percent of the total -- were from European countries not in the EU or the European Free Trade Association.
Another 21 percent were from North Africa and the Middle East; 17 percent from sub-Saharan Africa, and eight percent from the Americas.