pre_text: A reconciliation of the beginning and ending balance of unrecognized tax benefits is as follows: Included in the total unrecognized tax benefits at December 31, 2019, 2018 and 2017 is $2.4 billion, $2.3 billion and $1.9 billion, respectively, that if recognized, would favorably affect the effective income tax rate.
table: (dollars in millions)
table: 2019 2018 2017
table: Balance at January 1, $ 2,871 $2,355 $ 1,902
table: Additions based on tax positions related to the current year 149 160 219
table: Additions for tax positions of prior years 297 699 756
table: Reductions for tax positions of prior years (300) (248) (419)
table: Settlements (58) (40) (42)
table: Lapses of statutes of limitations (89) (55) (61)
table: Balance at December 31, $ 2,870 $ 2,871 $ 2,355
question: Analyse this data from a financial earnings document. What was the average settlements for 2017-2019?