Sales revenue declined by 4% to EUR 729.5m, but the year-on-year figures are not directly comparable, according to the company's annual report released on Thursday.

Sales are incomparable because its Macedonian subsidiary One, which was merged with Telekom Austria's Vip last year, was included in the consolidated financial statements for only the first seven months of the year.

The results are similarly affected by the sale of the Gibraltar venture Gibtelekom at the end of 2014.

Profit before interest, taxes, depreciation and amortisation (EBITDA), a key benchmark of profitability, rose by almost a fifth over the year before and was slightly higher than planned.

The financial statements shows the core company, which accounts for the bulk of operations, saw revenue decline marginally but its EBITDA rose by a third to EUR 166.3m and net profit more than doubled to EUR 46m.

Telekom said its user base was growing, as like-for-like figures show the number of mobile users rose by 3%, the number of TV subscribers by 6% and the number of fixed broadband connections by 4%.

Like most telecoms incumbents, Telekom has seen revenue from fixed telephony dwindle due to the transition to IT telephony and mobile.

However, the company says it has managed to offset the decline with a doubling of revenue from IT services, which amounted to EUR 26.6m last year.

The figures also reveal the core company's market position in Slovenia deteriorating, as it lost market share in all major segments bar VoIP services.

Most notably, its share of the mobile market declined by 2.1 percentage points year-on-year, though it remains the market leader with a share of 46.3%.

"The results that we achieved in 2015 prove that we are successfully implementing our strategy," CEO Rudolf Skobe was quoted as saying in the company's press release.

"We will continue developing services and strengthening the network in the coming period in which Telekom Slovenije will be transformed," he said.

After the failed privatisation in 2015, Telekom has been streamlining its operations, in particular in Slovenia.

The financial statements show the headcount at the core company dropped by 7% to 2,543 employees. Accordingly, labour costs at group level dropped by 6%.