Turkey's calendar-adjusted industrial production increased by 3.7 percent in October, compared to the previous month, surpassing expectations, the Turkish Statistical Institute (TurkStat) said in a statement Thursday.

The term "calendar adjusted" is used to refer to unadjusted data that has removed calendar and holiday-originated effects.TurkStat said that the calendar adjusted industrial production increased by 2.0% compared with the same month last year.

On an annual basis among the sub-indexes, the electricity, gas, steam and air conditioning sector led the advance with a 5.7 percent increase. It was followed by the manufacturing index with 1.7 percent and the mining and quarrying index, which saw a 0.4 percent increase, the statement said.

The 2.1 percent advance was a positive surprise for authorities and markets since surveys had showed weaker forecasts for industrial output in October.

According to a survey held by Anadolu Agency's Finance Desk on Monday, the median estimate for annual industrial production was 0.8 percent.

Among the sub-indexes, the manufacturing index had led the advance with a 4.1 percent increase on a month-on-month basis. The electricity, gas, steam and air conditioning index was estimated to see an advance of 2.9 percent, and the mining and quarrying index with 0.6 percent.

Turkey's industrial output is deemed as a vital indicator for economy as it is seen as a preliminary gouge for Gross Domestic Products (GDP) growth of the country, which officials repeatedly highlighted that it must be over 5 percent.