A reconciliation of the calculation of income tax on profit before tax at the statutory tax rate and income tax calculated according to the effective tax rate of the Group is as follows:

    Year ended December 31, 2016 Year ended December 31, 2015
GROSS PROFIT / (LOSS) 3,274 (3,756)
Income tax according to Polish statutory tax rate of 19% 621 (714)
Previous periods current income tax adjustments 16 (6)
Previous periods deferred income tax adjustments (36) (17)
Costs not recognized as tax-deductible costs 119 61
Non-taxable income (14) (26)
Other 2 (17)
TAX AT EFFECTIVE TAX RATE (Income tax (expense) as presented in the consolidated statements) 708 (719)
EFFECTIVE TAX RATE 22% 19%

Other differences presented in the comparative period concern mainly adjustments of deferred tax estimates made by the PGE Group subsidiaries.