Years Ended December 31,
2019
2018
Tax provision (benefit) at federal statutory rate
$ (11.9)
$ 38.3
Permanent differences
0.3
1.5
State tax, net of federal benefit
(7.3)
6.2
Foreign rate differential
1.4
(0.9)
Minority interest
0.2
(4.6)
Executive and stock compensation
2.5
3.5
Increase (decrease) in valuation allowance
(7.6)
(43.8)
Transaction costs
0.1
1.5
Tax credits generated/utilized
(2.2)
—
Return to provision
(6.0)
15.6
ASU 2017-11 adoption
(1.3)
—
Goodwill impairment
10.9
—
Gain/loss on sale or deconsolidation of a subsidiary
—
5.7
Bargain purchase gain
—
(24.2)
Other
(1.8)
3.6
Warrant liability
2.1
—
Income tax (benefit) expense
$ (20.6)
$ 2.4

text: 16. Income Taxes
text: The provisions (benefits) for income taxes differed from the amount computed by applying the federal statutory income tax rate to income (loss) before income taxes due to the following items for the years ended December 31, 2019 and 2018 (in millions):
text: The income tax benefit as of December 31, 2019 is $20.6 million. The benefit was primarily driven by a net valuation allowance release of $37.4 million related to the Insurance segment partially offset by an impairment of goodwill which is not deductible for tax purposes. The Insurance segment is profitable in 2019 and in a three-year overall cumulative income position as of December 31, 2019.
text: The profitability is driven by current year income associated with favorable claims and reserve development relative to expected. Further, unrealized gains from the investment portfolio continued to grow in 2019.
text: The amount recorded as of December 31, 2018 primarily relates to separate state filings that do not have net operating losses available to offset income. In the third quarter of 2018, the Insurance segment acquired Humana’s long-term care business, Kanawha Insurance Company. The combined insurance entity generated a net operating loss for the year due to additional tax deductions related to increases in policy holder reserves. In addition, the bargain purchase gain is not taxable. This net operating loss was carried forward but had a valuation allowance. Additionally, the income tax expense generated from the sale of BeneVir in the second quarter of 2018 is offset by tax attributes for which a valuation allowance had been recorded. Therefore, there is no net income tax expense recorded in the income statement for the sale.

Questions:
question: What was the income tax benefit in 2019?
answer: $20.6 million
question: What drove the income tax benefit?
answer: by a net valuation allowance release of $37.4 million related to the Insurance segment partially offset by an impairment of goodwill which is not deductible for tax purposes.
question: What was the value of minority interest in 2019?
answer: 0.2
scale: million
question: What was the change in the Tax provision (benefit) at federal statutory rate from 2018 to 2019?
answer: -50.2
derivation: -11.9 - 38.3
scale: million
question: What was the average Permanent differences value for 2018 and 2019?
answer: 0.9
derivation: (0.3 + 1.5) / 2
scale: million
question: What was the percentage change in the Foreign rate differential from 2018 to 2019?
answer: -2.56
derivation: 1.4 / -0.9 - 1
scale: percent