Year ended December 31,
2019
2018
2017
Basic:
Net earnings attributable to Black Knight
$108.8
$168.5
$182.3
Shares used for basic net earnings per share:
Weighted average shares of common stock outstanding
147.7
147.6
88.7
Basic net earnings per share
$0.74
$1.14
$2.06
Diluted:
Earnings before income taxes and equity in losses of unconsolidated affiliates
$192.4
Income tax benefit excluding the effect of noncontrolling interests
(32.2)
Net earnings
$224.6
Net earnings attributable to Black Knight
$108.8
$168.5
Shares used for diluted net earnings per share:
Weighted average shares of common stock outstanding
147.7
147.6
88.7
Dilutive effect of unvested restricted shares of common
stock
0.9
0.6
0.6
Weighted average shares of BKFS Class B common stock outstanding
—
—
63.1
Weighted average shares of common stock, diluted
148.6
148.2
152.4
Diluted net earnings per share
$0.73
$1.14
$1.47

text: (5) Earnings Per Share
text: Basic earnings per share is computed by dividing Net earnings attributable to Black Knight by the weighted-average number of shares of common stock outstanding during the period.
text: For the periods presented, potentially dilutive securities include unvested restricted stock awards and the shares of BKFS Class B common stock prior to the Distribution. For the year ended December 31, 2017, the numerator in the diluted net earnings per share calculation is adjusted to reflect our income tax expense at an expected effective tax rate assuming the conversion of the shares of BKFS Class B common stock into shares of BKFS Class A common stock on a one-for-one basis prior to the Distribution. The effective tax rate for the year ended December 31, 2017 was (16.7)%, including the effect of the benefit related to the revaluation of our net deferred income tax liability and certain other discrete items recorded during 2017. For the year ended December 31, 2017, the denominator includes approximately 63.1 million shares of BKFS Class B common stock outstanding prior to the Distribution. The denominator also includes the dilutive effect of approximately 0.9 million, 0.6 million and 0.6 million shares of unvested restricted shares of common stock for the years ended December 31, 2019, 2018 and 2017, respectively.
text: The shares of BKFS Class B common stock did not share in the earnings or losses of Black Knight and were, therefore, not participating securities. Accordingly, basic and diluted net earnings per share of BKFS Class B common stock have not been presented.
text: The computation of basic and diluted earnings per share is as follows (in millions, except per share amounts):

Questions:
question: How did the company compute basic earnings per share?
answer: dividing Net earnings attributable to Black Knight by the weighted-average number of shares of common stock outstanding during the period.
question: What years does the table provide information for the computation of basic and diluted earnings per share is as follows (in millions, except per share?
answer: 2019
2018
2017
question: What were the basic Net earnings attributable to Black Knight in 2017?
answer: 182.3
scale: million
question: What was the change in the basic net earnings attributable to Black Knight between 2017 and 2018?
answer: -13.8
derivation: 168.5-182.3
scale: million
question: What was the change in the basic net earnings per share between 2017 and 2019?
answer: -1.32
derivation: 0.74-2.06
question: What was the percentage change in Diluted net earnings per share between 2018 and 2019?
answer: -35.96
derivation: (0.73-1.14)/1.14
scale: percent