8.  INCOME TAXES    

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Our effective tax rates were 23.2 percent and 22.0 percent for the three and nine months ended September 30, 2019, respectively. The effective tax rates for the three and nine months ended September 30, 2018, were 25.2 percent and 23.1 percent, respectively. The 2019 rates are lower due to the impact of discrete benefits related to share-based compensation and a favorable return to accrual adjustment when compared to prior year, partially offset by the impact of state tax rate changes.

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A tax benefit of $1.3 million and $5.1 million related to share-based compensation was recognized in our Condensed Consolidated Statements of Operations as a discrete item in income tax expense for the three and nine months ended September 30, 2019, respectively.

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At September 30, 2019, the net deferred tax liability of $161.7 million consisted of net long-term deferred tax assets of $11.8 million and net long-term deferred tax liabilities of $173.5 million. The change in the net deferred tax liability was primarily related to purchase accounting adjustments in connection with the acquisition of USI and related tax elections and a return to accrual adjustment for 2018 tax returns filed in 2019, partially offset by state tax rate changes.