* As adjusted to reflect the impact of the full retrospective adoption of IFRS 15. See Note 2 for further details.
The U.S. Tax Cuts and Jobs Act (the “Tax Act”) enacted on December 22, 2017 introduces a number of changes to U.S. income tax law. Among other changes, the Tax Act (i) reduces the U.S. federal corporate tax rate from 35% to 21%, (ii) enacts limitations regarding the deductibility of interest expense, (iii) modifies the provisions relating to the limitations on deductions for executive compensation of publicly traded corporations, (iv) imposes new limitations on the utilization of net operating loss arising in taxable years beginning after December 31, 2017, (v) repeals the corporate alternative minimum tax and provides for a refund of existing alternative minimum tax credits, and (vi) creates new taxes on certain foreign-sourced earnings and certain related-party payments, which are referred to as the global intangible low-taxed income tax and the base erosion tax, respectively.
As a result of the new U.S. federal statutory corporate tax rate of 21% contained within the Tax Act, the Group recorded non-cash charges of $16.9 million to tax expense and $16.9 million to equity to revalue the Group’s U.S. net deferred tax assets during fiscal year 2018.
In June 2019 and December 2017, as a result of the Group’s assessment of the realizability of its Australian and U.S. deferred tax assets, the Group recorded non-cash charges to tax expense of $54.7 million and $30.4 million, respectively, and $25.8 million to equity in December 2017 to reduce the carrying value of these assets. The assessment of the realizability of the Australian and U.S. deferred tax assets is based on all available positive and negative evidence. Such evidence includes, but is not limited to, recent cumulative earnings or losses, expectations of future taxable income by taxing jurisdiction, and the carry-forward periods available for the utilization of deferred tax assets. The Group will continue to assess and record any necessary changes to align its deferred tax assets to their realizable value.
In December 2017, the Group made changes to its corporate structure to include certain foreign subsidiaries in its U.S. consolidated tax group that resulted in the creation of certain deferred tax assets and liabilities, including a non-recognized deferred tax asset of $2.1 billion related to the fair market value of its intellectual property. The assets are included in the Group’s quarterly assessment and are only recognized to the extent they are determined to be realizable.
The impact on the net deferred tax asset from business combinations of $19.1 million in fiscal year 2019 represents the net deferred tax assets and liabilities recognized as a result of the acquisition of OpsGenie. The Group acquired net operating loss carryforward deferred tax assets of approximately $1.8 million from OpsGenie. The Group also recognized deferred tax liabilities of approximately $19.6 million primarily related to acquired intangibles from OpsGenie, the amortization of which will not be deductible from future taxable profits.
Table:
 | 2019 | 2018
 | (U.S. $ in thousands) | 
 |  | *As Adjusted
Reconciliation of deferred tax assets, net |  | 
Balance at the beginning of | $47,060 | $140,532
Deferred tax expense for the year | (15,916) | (53,297)
Debited to equity | (8,884) | (40,092)
Adjustment in respect of income tax payable | — | (83)
Impact from business combinations | (19,092) | —
Currency revaluation impact | 44 | —
Balance at the ending of | $3,212 | $47,060


Question: What is the percentage change of deferred tax expenses between fiscal year 2018 to 2019?
Answer: -70.14
Calculation: (-15,916-(-53,297))/(-53,297)