ANKARA (AFP) -- Turkey's estimated unemployment rate fell to 10.5 percent in the three months to the end of January from 11.2 percent in the same period last year, the State Statistics Institute said Thursday.

A survey based on interviews of about 89,500 people showed the number of jobless down by 94,000 to 2,608,000.

The unemployment rate was estimated at 9.9 percent for the whole of 2006, down from 10.3 percent in 2005.

High unemployment remains a major challenge for the Turkish government, despite several years of strong growth.

To determine the jobless rate, the statistics institute surveys households in different regions of the country and uses the results to make a nationwide three-month projection.

The figures provide the only unemployment data in Turkey.

But experts say they do not reflect the overall picture of under-employment because they exclude undeclared or hidden unemployment, or the employment of educated, qualified people in menial, unqualified jobs.

However, standard unemployment data in industrialized countries covers only people registered as unemployed and available for work.