Table:
|  |  | Fiscal |  |
| --- | --- | --- | --- |
|  | 2019 | 2018 | 2017 |
| Cost of sales | $4,880 | $4,403 | $3,541 |
| Research and development | 2,990 | 3,247 | 2,973 |
| Selling, general and administrative | 28,596 | 25,088 | 23,911 |
| Income tax benefit | (4,946) | (5,073) | (7,073) |
|  | $31,520 | $27,665 | $23,352 |
Paragraphs:
Stock Compensation Expense
The following table shows total stock-based compensation expense and related tax benefits included in the Consolidated Statements of Operations for fiscal 2019, 2018 and 2017 (in thousands):
As a result of our acquisition of Rofin on November 7, 2016, we made a payment of $15.3 million due to the cancellation of options held by employees of Rofin. The payment was allocated between total estimated merger consideration of $11.1 million and post-merger stock-based compensation expense of $4.2 million, recorded in the first quarter of fiscal 2017, based on the portion of the total service period of the underlying options that have not been completed by the merger date.
During fiscal 2019, $4.8 million of stock-based compensation cost was capitalized as part of inventory for all stock plans, $4.8 million was amortized into cost of sales and $1.5 million remained in inventory at September 28, 2019. During fiscal 2018, $4.7 million of stock-based compensation cost was capitalized as part of inventory for all stock plans, $4.4 million was amortized into cost of sales and $1.5 million remained in inventory at September 29, 2018.
At fiscal 2019 year-end, the total compensation cost related to unvested stock-based awards granted to employees under our stock plans but not yet recognized was approximately $33.1 million. We do not estimate forfeitures. This cost will be amortized on a straight-line basis over a weighted-average period of approximately 1.5 years.
Question:
In which years was cost of sales calculated?
Answer: 2019, 2018, 2017