19. Income Taxes

The calculation of the tax charge is as follows:


	2017		2016		2015
	(€ in thousands)
Income tax based on domestic rate	10,918		9,776		5,208
Tax effect of:
Non-deductible expenses	(634)		(622)		(309)
Tax incentives	—		(46)		136
Current year losses for which no deferred tax asset was recognized	(10,257)		(9,045)		(5,035)
Change in unrecognized deductible temporary differences	(25)		(63)		—
Income tax charge	2		—		—
Effective tax rate	—	%	—	%	—	%

Due to the operating losses incurred since inception the Company has no tax provisions as of the balance sheet date. Furthermore, no significant temporary differences exist between accounting and tax results.

Realization of deferred tax assets is dependent on future earnings, if any, the timing and amount of which are uncertain. Accordingly, the Company has not yet recognized any deferred tax asset related to operating losses. As per December 31, 2017, the Company has a total amount of € 123.9 million (2016: € 82.9 million, 2015: € 46.9 million) tax loss carry-forwards available for offset against future taxable profits. According to current tax regulations the first amount of the tax loss carry-forwards will expire in 2021.