82 | 2017 form 10-k a reconciliation of the beginning and ending amount of gross unrecognized tax benefits for uncertain tax positions , including positions impacting only the timing of tax benefits , follows . reconciliation of unrecognized tax benefits:1 years a0ended a0december a031 .

Table: ( millions of dollars ) years ended december 31 , 2017 years ended december 31 , 2016 balance at january 1, $ 1032 $ 968 additions for tax positions related to current year 270 73 additions for tax positions related to prior years 20 55 reductions for tax positions related to prior years -27 ( 27 ) -36 ( 36 ) reductions for settlements2 -9 ( 9 ) -24 ( 24 ) reductions for expiration of statute of limitations 2014 -4 ( 4 ) balance at december 31, $ 1286 $ 1032 amount that if recognized would impact the effective tax rate $ 1209 $ 963

1 foreign currency impacts are included within each line as applicable . 2 includes cash payment or other reduction of assets to settle liability . we classify interest and penalties on income taxes as a component of the provision for income taxes . we recognized a net provision for interest and penalties of $ 38 million , $ 34 million and $ 20 million during the years ended december 31 , 2017 , 2016 and 2015 , respectively . the total amount of interest and penalties accrued was $ 157 million and $ 120 million as of december a031 , 2017 and 2016 , respectively . on january 31 , 2018 , we received a revenue agent 2019s report from the irs indicating the end of the field examination of our u.s . income tax returns for 2010 to 2012 . in the audits of 2007 to 2012 including the impact of a loss carryback to 2005 , the irs has proposed to tax in the united states profits earned from certain parts transactions by csarl , based on the irs examination team 2019s application of the 201csubstance-over-form 201d or 201cassignment-of-income 201d judicial doctrines . we are vigorously contesting the proposed increases to tax and penalties for these years of approximately $ 2.3 billion . we believe that the relevant transactions complied with applicable tax laws and did not violate judicial doctrines . we have filed u.s . income tax returns on this same basis for years after 2012 . based on the information currently available , we do not anticipate a significant increase or decrease to our unrecognized tax benefits for this matter within the next 12 months . we currently believe the ultimate disposition of this matter will not have a material adverse effect on our consolidated financial position , liquidity or results of operations . with the exception of a loss carryback to 2005 , tax years prior to 2007 are generally no longer subject to u.s . tax assessment . in our major non-u.s . jurisdictions including australia , brazil , china , germany , japan , mexico , switzerland , singapore and the u.k. , tax years are typically subject to examination for three to ten years . due to the uncertainty related to the timing and potential outcome of audits , we cannot estimate the range of reasonably possible change in unrecognized tax benefits in the next 12 months. .

Question: what was the average provision for interest and penalties for the period december 31 , 2015 to 2017 , in millions?
Answer: 30.7
Calculation: divide(add(20, add(38, 34)), const_3)