ITEM 6. SELECTED FINANCIAL DATA
Financial Highlights (dollars in thousands, except per share amounts)
(1) During fiscal 2019, the Company recorded $7.0 million of special tax expense in accordance with regulations under U.S. Tax Reform, and reasserted that certain historical undistributed earnings of two foreign subsidiaries will be permanently reinvested, resulting in a $10.5 million benefit.
(2) During fiscal 2019, the Company recorded $1.7 million, $1.5 million net of taxes, in restructuring costs, which are included in operating income.
(3) During fiscal 2018, the Company recorded $85.9 million of non-recurring income tax expense due to the enactment of U.S. Tax Reform and paid a $13.5 million one-time non-executive employee bonus.
(4) During fiscal 2016, the Company recorded $7.0 million in restructuring costs and $5.2 million in selling and administrative expenses, which are included in operating income. The $7.0 million was largely related to the Company's closure of its manufacturing facility in Fremont, California, and the partial closure of its Livingston, Scotland facility. The $5.2 million was related to accelerated share-based compensation expense recorded pursuant to the retirement agreement with the Company's former Chief Executive Officer. During fiscal 2015 the Company recorded $1.7 million of restructuring costs, largely related to the Company's consolidation of its manufacturing facilities in Wisconsin, as well as its relocation of manufacturing operations from Juarez, Mexico to Guadalajara, Mexico.
(5) The Company defines return on invested capital ("ROIC"), a non-GAAP financial measure, as tax-effected operating income divided by average invested capital over a rolling five-quarter period. Invested capital is defined as equity plus debt, less cash and cash equivalents, as discussed in Part II, Item 7, "Management’s Discussion and Analysis of Financial Condition and Results of Operations - Return on Invested Capital ("ROIC") and Economic Return." For a reconciliation of ROIC and Economic Return to our financial statements that were prepared in accordance with GAAP, see Exhibit 99.1 to this annual report on Form 10-K.
(6) Fiscal 2015 included 53 weeks. All other periods presented included 52 weeks.

Fiscal Years Ended
Income Statement Data 
September 28,
2019
September 29,
2018
September 30,
2017
October 1,
2016
October 3,
2015(6)
Net sales
$3,164,434
$2,873,508
$2,528,052
$2,556,004
$2,654,290
Gross profit
291,838
257,600
255,855
227,359
239,550
Gross margin percentage
9.2%
9.0%
10.1%
8.9%
9.0%
Operating income (2) (3) (4)
142,055
118,283
129,908
99,439
115,436
Operating margin percentage (2) (3) (4)
4.5%
4.1%
5.1%
3.9%
4.3%
Net income (1) (2) (3) (4)
108,616
13,040
112,062
76,427
94,332
Earnings per share (diluted) (1) (2) (3) (4)
$3.50
$0.38
$3.24
$2.24
$2.74
Cash Flow Statement Data
Cash flows provided by operations
$115,300
$66,831
$171,734
$127,738
$76,572
Capital equipment additions
90,600
62,780
38,538
31,123
35,076
Balance Sheet Data
Total assets
$2,000,883
$1,932,642
$1,976,182
$1,765,819
$1,691,760
Total debt obligations
287,980
188,617
313,107
262,509
261,806
Shareholders’ equity
865,576
921,143
1,025,939
916,797
842,272
Return on invested capital (5)
13.1%
16.1%
16.2%
13.8%
14.0%
Inventory turnover ratio
3.8x 
3.6x 
3.7x 
4.2x 
4.3x


Question: Analyse this data from a financial earnings document. What was the change in the gross profit between 2015 and 2016?
Choices:
215168
227356
-12
-239547
-12191
Correct choice index: 4