Qatar's population has more than doubled in the past six years to 1.69 million as the tiny Gulf state's economy continues to expand, preliminary results of a census showed this week.

The number of people residing in the country jumped from about 744,000 in 2004 when the last census was taken, data from the country's statistics authority showed.

Qatar's economy has rocketed on the back of increased natural gas production, with its total population expected to nearly double by 2026 to 3 million, according to the Ministry of Municipality and Urban Planning.

Its copious supplies of natural gas have turned it into the world's wealthiest country per capita. Though small -- its native population numbers only just over 200,000 - its booming economy far outpaces its Gulf neighbours and western countries.

Much of the growth in population has resulted from a steady stream of Western expats and migrant workers in recent years who have sought to benefit from the country's robust economy.

But many analysts expect population growth to taper off as the country's energy projects are completed.

'It has been an exceptionally rapid phase of economic growth, and that's required strong gains in the workforce. As the economy matures, the pace of demographic growth will moderate as well,' said Simon Williams, chief economist for HSBC Middle East.

'Many people are involved in the buildout of Qatar's energy infrastructure - when the work is done, they will go home.'

Housing units in the country increased, with the number of apartments jumping by 146 percent since 2004, the data showed. About 18,000 new buildings are under construction.

'We believe Qatar's population will continue to grow at an steady base of 5.3 per year, as there are still plenty of untapped resources in the country, including some energy-related resources that would fuel growth in the foreseeable future and serve as a magnet for expatriates,' said Farah Ahmed Hersi, senior economist at Masraf al Rayan.

Hersi expects Qatar's population to reach 1.8 million by the end of 2010, and 2.03 million by 2013. The world's largest liquefied natural gas (LNG) exporter has spent billions of dollars to boost its LNG output.

It is expected to reach its target annual capacity of 77 million tonnes of LNG this year, ending a massive expansion plan that has seen it become the top LNG exporter after shipping its first cargo 14 years ago.

A Reuters poll in April showed Qatar's economy was likely to expand by 16.1 percent this year.

The Opec member is set to largely outperform its fellow oil producers in the Gulf such as Saudi Arabia and the UAE in the coming years, helped by expansion of its gas facilities and generous government infrastructure spending.-Reuters