What does the following information mean? why?

The Companys effective income tax rate, as calculated by dividing income tax expense (benefit) by income (loss) before income taxes, was (14.1)% for 2018, (63.2)% for 2017 and 38.9% for 2016. The following table provides a reconciliation of income tax expense (benefit) at the statutory federal rate to actual income tax expense (benefit).

The Companys effective tax rate, as calculated by dividing income tax expense (benefit) by income (loss) before income taxes minus net income attributable to noncontrolling interest, was (10.3)% for 2018, (70.3)% for 2017 and 41.8% for 2016.

On December 22, 2017, the Tax Act was signed into law and significantly reformed the Internal Revenue Code of 1986, as amended.

As of December 31, 2017, the Company completed its estimate for the tax effects of the enactment of the Tax Act, and as a result, the Company revalued and reduced its net deferred tax liability to the newly enacted corporate tax rate of 21%. The Company recognized an estimated benefit of $69.0 million, primarily as a result of revaluing its net deferred tax liability. This benefit was partially offset by a $2.4 million increase to the valuation allowance as a result of the deductibility of certain deferred compensation based on the current interpretation of the Tax Act. The net benefit of $66.6 million was recorded to income tax expense (benefit) in the 2017 consolidated financial statements. During the third quarter of 2018, the Company recorded an additional tax benefit of $1.9 million attributable to the re-measurement of its net deferred tax liability in connection with the filing of its 2017 federal income tax return.

The amounts recorded to gain (loss) on exchange transactions on the consolidated statements of operations did not have a significant impact on the effective income tax rate for any periods presented.

The Company records liabilities for uncertain tax positions related to certain income tax positions. These liabilities reflect the Companys best estimate of the ultimate income tax liability based on currently known facts and information. Material changes in facts or information, as well as the expiration of statute and/or settlements with individual tax jurisdictions, may result in material adjustments to these estimates in the future.

The Company recognizes potential interest and penalties related to uncertain tax positions in income tax expense (benefit). During 2018, 2017 and 2016, the interest and penalties related to uncertain tax positions recognized in income tax expense (benefit) were not material. In addition, the amount of interest and penalties accrued at December 30, 2018 and December 31, 2017 were not material.

The Company had uncertain tax positions, including accrued interest of $3.1 million on December 30, 2018 and $2.4 million on December 31, 2017, all of which would affect the Companys effective tax rate if recognized. While it is expected the amount of uncertain tax positions may change in the next 12 months, the Company does not expect such change would have a significant impact on the consolidated financial statements.

The Companys deferred income tax assets and liabilities are subject to adjustment in future periods based on the Companys ongoing evaluations of such deferred assets and liabilities and new information available to the Company.

Valuation allowances are recognized on deferred tax assets if the Company believes it is more likely than not that some or all of the deferred tax assets will not be realized. The Company believes the majority of the deferred tax assets will be realized due to the reversal of certain significant temporary differences and anticipated future taxable income from operations.

The valuation allowance of $5.9 million on December 30, 2018 and $4.3 million on December 31, 2017 was established primarily for certain loss carryforwards and deferred compensation. The increase in the valuation allowance as of December 30, 2018 was primarily a result of the deductibility of certain deferred tax assets following the Companys adoption of the Tax Act.

As of December 30, 2018, the Company had $16.2 million of federal net operating losses, which do not expire, and $93.5 million of state net operating losses available to reduce future income taxes, which expire in varying amounts through 2038.

Prior tax years beginning in year 2002 remain open to examination by the IRS, and various tax years beginning in year 1998 remain open to examination by certain state tax jurisdictions due to loss carryforwards.