Jordan has launched a national census to provide greater clarity about a population that includes large numbers of Syrian refugees and foreign workers.

Some 21,000 field researchers began visiting homes Monday, for the first time using electronic tablets for data entry. Official results will be released in February.

One key figure will be the number of Syrian refugees, which will help determine how much foreign aid Jordan can request.

The U.N. refugee agency says some 628,000 registered refugees are in Jordan, but growing numbers have left regional host countries for Europe.

Planning Minister Imad Fakhoury says the government, using social media, has assured unregistered refugees and foreign workers that they will not face repercussions when participating in the census.

A 2004 census counted 5.1 million people living in Jordan.