{"pre_text": ["american tower corporation and subsidiaries notes to consolidated financial statements the company expects the unrecognized tax benefits to change over the next 12 months if certain tax matters ultimately settle with the applicable taxing jurisdiction during this timeframe , or if the applicable statute of limitations lapses .", "the impact of the amount of such changes to previously recorded uncertain tax positions could range from zero to $ 10.8 million .", "a reconciliation of the beginning and ending amount of unrecognized tax benefits are as follows for the years ended december 31 , ( in thousands ) : ."], "post_text": ["during the years ended december 31 , 2016 , 2015 and 2014 , the statute of limitations on certain unrecognized tax benefits lapsed and certain positions were effectively settled , which resulted in a decrease of $ 3.2 million , $ 3.5 million and $ 5.3 million , respectively , in the liability for uncertain tax benefits , all of which reduced the income tax provision .", "the company recorded penalties and tax-related interest expense to the tax provision of $ 9.2 million , $ 3.2 million and $ 6.5 million for the years ended december 31 , 2016 , 2015 and 2014 , respectively .", "in addition , due to the expiration of the statute of limitations in certain jurisdictions , the company reduced its liability for penalties and income tax-related interest expense related to uncertain tax positions during the years ended december 31 , 2016 , 2015 and 2014 by $ 3.4 million , $ 3.1 million and $ 9.9 million , respectively .", "as of december 31 , 2016 and 2015 , the total amount of accrued income tax-related interest and penalties included in the consolidated balance sheets were $ 24.3 million and $ 20.2 million , respectively .", "the company has filed for prior taxable years , and for its taxable year ended december 31 , 2016 will file , numerous consolidated and separate income tax returns , including u.s .", "federal and state tax returns and foreign tax returns .", "the company is subject to examination in the u.s .", "and various state and foreign jurisdictions for certain tax years .", "as a result of the company 2019s ability to carryforward federal , state and foreign nols , the applicable tax years generally remain open to examination several years after the applicable loss carryforwards have been used or have expired .", "the company regularly assesses the likelihood of additional assessments in each of the tax jurisdictions resulting from these examinations .", "the company believes that adequate provisions have been made for income taxes for all periods through december 31 , 2016 .", "13 .", "stock-based compensation summary of stock-based compensation plans 2014the company maintains equity incentive plans that provide for the grant of stock-based awards to its directors , officers and employees .", "the 2007 equity incentive plan ( the 201c2007 plan 201d ) provides for the grant of non-qualified and incentive stock options , as well as restricted stock units , restricted stock and other stock-based awards .", "exercise prices in the case of non-qualified and incentive stock options are not less than the fair value of the underlying common stock on the date of grant .", "equity awards typically vest ratably , generally over four years for rsus and stock options and three years for psus .", "stock options generally expire 10 years from the date of grant .", "as of december 31 , 2016 , the company had the ability to grant stock-based awards with respect to an aggregate of 9.5 million shares of common stock under the 2007 plan .", "in addition , the company maintains an employee stock purchase plan ( the 201cespp 201d ) pursuant to which eligible employees may purchase shares of the company 2019s common stock on the last day of each bi-annual offering period at a discount of the lower of the closing market value on the first or last day of such offering period .", "the offering periods run from june 1 through november 30 and from december 1 through may 31 of each year .", "during the years ended december 31 , 2016 , 2015 and 2014 , the company recorded and capitalized the following stock-based compensation expenses ( in thousands ) : ."], "table": [["", "2016", "2015", "2014"], ["balance at january 1", "$ 28114", "$ 31947", "$ 32545"], ["additions based on tax positions related to the current year", "82912", "5042", "4187"], ["additions for tax positions of prior years", "2014", "2014", "3780"], ["foreign currency", "-307 ( 307 )", "-5371 ( 5371 )", "-3216 ( 3216 )"], ["reduction as a result of the lapse of statute of limitations and effective settlements", "-3168 ( 3168 )", "-3504 ( 3504 )", "-5349 ( 5349 )"], ["balance at december 31", "$ 107551", "$ 28114", "$ 31947"]], "table_ori": [["", "2016", "2015", "2014"], ["Balance at January 1", "$28,114", "$31,947", "$32,545"], ["Additions based on tax positions related to the current year", "82,912", "5,042", "4,187"], ["Additions for tax positions of prior years", "—", "—", "3,780"], ["Foreign currency", "(307)", "(5,371)", "(3,216)"], ["Reduction as a result of the lapse of statute of limitations and effective settlements", "(3,168)", "(3,504)", "(5,349)"], ["Balance at December 31", "$107,551", "$28,114", "$31,947"]]}

Question: what is the net change in the balance of unrecognized tax benefits during 2015?
Evidence:
table_1: the balance at january 1 of 2016 is $ 28114 ; the balance at january 1 of 2015 is $ 31947 ; the balance at january 1 of 2014 is $ 32545 ;
table_6: the balance at december 31 of 2016 is $ 107551 ; the balance at december 31 of 2015 is $ 28114 ; the balance at december 31 of 2014 is $ 31947 ;
Program: subtract(28114, 31947)
Answer:
str_answer: -3833
exe_answer: -3833