Task: Table-QA (source dataset: FinQA)

Task: 
You are given a table containing structured data and a natural language question referring to the table. Your goal is to analyze the table and provide an accurate and concise answer based on the given data.

Instructions:
1. Understand the Table: Examine the structure, headers, and data in the table. Identify relevant columns and rows related to the question.
2. Interpret the Question: Determine whether the question requires direct retrieval, aggregation, comparison, sorting, filtering, or inference.
3. Extract the Answer: Use logical reasoning and numerical operations (if necessary) to derive the correct response from the table.
4. Format the Answer: No explanation, return the answer in a structured JSON format: {"answer": <answer>}. If the question cannot be answered due to missing or ambiguous data, return a JSON response with {"answer": null}.

Table:
| ( millions )                                                       | 2008       | 2007     |
|:-------------------------------------------------------------------|:-----------|:---------|
| balance at january 1                                               | $ 110      | $ 77     |
| additions based on tax positions related to the current year       | 12         | 21       |
| additions for tax positions of prior years                         | 5          | 19       |
| reductions for tax positions of prior years                        | -17 ( 17 ) | -5 ( 5 ) |
| pre-acquisition unrecognized tax benefits                          | 20         | 2014     |
| reductions for expiration of the applicable statute of limitations | -6 ( 6 )   | -5 ( 5 ) |
| settlements                                                        | -21 ( 21 ) | -1 ( 1 ) |
| currency                                                           | -4 ( 4 )   | 4        |
| balance at december 31                                             | $ 99       | $ 110    |

Question:
what was the net change in the accrued liability for unrecognized tax benefits from 2007 to 2008?


pre_text: notes to the consolidated financial statements the activity in the accrued liability for unrecognized tax benefits for the two years ended december 31 , 2008 was as follows : ( millions ) 2008 2007 .
post_text: balance at december 31 $ 99 $ 110 the amount of unrecognized tax benefits was $ 99 million and $ 110 million as of december 31 , 2008 and 2007 , respectively .
if recognized , $ 89 million and $ 88 million would impact the effective rate as of december 31 , 2008 and 2007 , respectively .
the company recognizes accrued interest and penalties related to unrecognized tax benefits in income tax expense .
the company had accrued $ 10 million and $ 9 million for estimated interest and penalties on unrecognized tax benefits as of december 31 , 2008 and 2007 , respectively .
the company recognized $ 1 million and $ 3 million of expense for estimated interest and penalties during the years ended december 31 , 2008 and 2007 , respectively .
while it is expected that the amount of unrecognized tax benefits will change in the next 12 months , quantification of an estimated range cannot be made at this time .
the company does not expect this change to have a significant impact on the results of operations or financial position of the company , however , actual settlements may differ from amounts accrued .
14 .
pensions and other postretirement benefits defined benefit plans ppg has defined benefit pension plans that cover certain employees worldwide .
ppg also sponsors welfare benefit plans that provide postretirement medical and life insurance benefits for certain u.s .
and canadian employees and their dependents .
these programs require retiree contributions based on retiree-selected coverage levels for certain retirees and their dependents and provide for sharing of future benefit cost increases between ppg and participants based on management discretion .
the company has the right to modify or terminate certain of these benefit plans in the future .
salaried and certain hourly employees hired on or after october 1 , 2004 , are not eligible for postretirement medical benefits .
salaried employees hired , rehired or transferred to salaried status on or after january 1 , 2006 , and certain hourly employees hired in 2006 or thereafter are eligible to participate in a defined contribution retirement plan .
these employees are not eligible for defined benefit pension plan benefits .
the medicare act of 2003 introduced a prescription drug benefit under medicare ( 201cmedicare part d 201d ) that provides several options for medicare eligible participants and employers , including a federal subsidy payable to companies that elect to provide a retiree prescription drug benefit which is at least actuarially equivalent to medicare part d .
during the third quarter of 2004 , ppg concluded its evaluation of the provisions of the medicare act and decided to maintain its retiree prescription drug program and to take the subsidy available under the medicare act .
the impact of the medicare act was accounted for in accordance with fasb staff position no .
106-2 , 201caccounting and disclosure requirements related to the medicare prescription drug , improvement and modernization act of 2003 201d effective january 1 , 2004 .
in addition , the plan was amended september 1 , 2004 , to provide that ppg management will determine the extent to which future increases in the cost of its retiree medical and prescription drug programs will be shared by certain retirees .
the federal subsidy related to providing a retiree prescription drug benefit is not subject to u.s .
federal income tax and is recorded as a reduction in annual net periodic benefit cost of other postretirement benefits .
in august 2007 , the company 2019s u.s .
other postretirement benefit plan was amended to consolidate the number of retiree health care options available for certain retirees and their dependents .
the plan amendment was effective january 1 , 2008 .
the amended plan also offers a fully-insured medicare part d prescription drug plan for certain retirees and their dependents .
as such , beginning in 2008 ppg is no longer eligible to receive the subsidy provided under the medicare act of 2003 for these retirees and their dependents .
the impact of the plan amendment was to reduce the accumulated plan benefit obligation by $ 57 million .
50 2008 ppg annual report and form 10-k .
label: -11
qa: answer: -11
ann_table_rows: 9
steps: op: minus1-1
arg1: 99
arg2: 110
res: -11
program: subtract(99, 110)
gold_inds: table_9: ( millions ) the balance at december 31 of 2008 is $ 99 ; the balance at december 31 of 2007 is $ 110 ;
exe_ans: -11
tfidftopn: text_0: notes to the consolidated financial statements the activity in the accrued liability for unrecognized tax benefits for the two years ended december 31 , 2008 was as follows : ( millions ) 2008 2007 .
text_3: the company recognizes accrued interest and penalties related to unrecognized tax benefits in income tax expense .
program_re: subtract(99, 110)
model_input: table_1
( millions ) the balance at january 1 of 2008 is $ 110 ; the balance at january 1 of 2007 is $ 77 ;
table_9
( millions ) the balance at december 31 of 2008 is $ 99 ; the balance at december 31 of 2007 is $ 110 ;
text_1
balance at december 31 $ 99 $ 110 the amount of unrecognized tax benefits was $ 99 million and $ 110 million as of december 31 , 2008 and 2007 , respectively .