pre_text: Basic and Diluted Net Income Per Share
  Basic net income per share is computed using net income divided by the weighted average number of shares of common stock
  outstanding (“Weighted Shares”) for the period presented. Diluted net income per share is computed using net income divided by Weighted Shares and the treasury stock method effect of common equivalent shares (“CESs”) outstanding for each period presented. In the following table, we present a reconciliation of earnings per share and the shares used in the computation of earnings per share for the years ended December 31, 2019, 2018 and 2017 (in thousands, except per share data):
  common equivalent shares (“CESs”) outstanding for each period presented. In the following table, we present a reconciliation of
  earnings per share and the shares used in the computation of earnings per share for the years ended December 31, 2019, 2018 and
  2017 (in thousands, except per share data): The number of anti-dilutive CESs in 2019, 2018 and 2017 was immaterial. See Note 2 for further information on those securities.
table: Year Ended December 31,
table: 2019 2018 2017
table: (in thousands, except per share data)   
table: Net income    $ 85,762 $ 104,690 $ 116,481
table: Earnings per share：
table: Basic    $ 1.33 $ 1.58 $ 1.68
table: Effect of CESs      (0.01 )    - -
table: Diluted    $ 1.32 $ 1.58 $ 1.68
table: Weighted average number of shares:
table: Basic      64,397 66,201 69,175
table: Effect of CESs      706 233 249
table: Diluted      65,103 66,434 69,424
question: Analyse this data from a financial earnings document. What is change for basic earning per share between 2019 and 2018?