The 17th census of Population and Housing is underway, with Census Day being next Sunday, the National Statistics Office said.

It said in a statement that 1,021 enumerators, 91 supervisors and 28 call centre operators are involved in this year's census, which will provide an important and updated source of information about the count, characteristics, composition and condition of the population of Malta.

Census results influence a number of aspects of Maltese life: public policy-making; options and decisions of families and households; choices made by the elderly; initiatives and investments by the business sector; streams of research and development.

Census questionnaires were mailed in the last week of October and started being collected on November 7. The collection will continue until December 4 and all residents are required by law to participate.

To date, nearly 50,000 questionnaires have been collected, covering more than 138,000 persons.

The NSO is also operating a call centre, which manages all calls received through freephone 170.

Between October 26, when the service was launched, and yesterday 15,980 calls were received. Of these, 14,323, or 90 per cent, were answered. The census has a dedicated website at www.census2011.gov.mt .

Since the first official census, the population of Malta has increased three-and-a-half times over - from 114,499 in 1842 to 404,962 in 2005. While the population increased by over 60 per cent between 1842 and the turn of the 20th century, the population more than doubled between the beginning of the 20th century and the turn of the 21st, between 1901 and 2005.

In the last census the population grew by 7.1 per cent when compared to the one taken a decade earlier, indicating a slowdown in population growth.

In fact, in the period between 1985 and 1995, the population had grown by 9.5 per cent.