Table:
| Fiscal Year Ended |  |  |  |  |
| --- | --- | --- | --- | --- |
|  | December 28, 2019 | December 29, 2018 | $ Change | % Change |
| (Dollars in thousands) |  |  |  |  |
| Research and development | $81,499 | $74,976 | $6,523 | 8.7 % |
| % of revenues | 13.8 % | 14.2 % |  |  |
| Fiscal Year Ended |  |  |  |  |
|  | December 29, 2018 | December 30, 2017 | $ Change | % Change |
| (Dollars in thousands) |  |  |  |  |
| Research and development | $74,976 | $73,807 | $1,169 | 1.6 % |
| % of revenues | 14.2 % | 13.5 % |  |  |
Paragraphs:
Research and Development
The increase in research and development expenses in fiscal 2019 compared to fiscal 2018 was primarily driven by an increase in employee compensation costs caused by increases in headcount, annual compensation and benefit adjustments and employee performance-based compensation, partially offset by a decrease in project material costs.
Question:
What led to increase in research and development expenses in fiscal 2019 compared to fiscal 2018?
Answer: The increase in research and development expenses in fiscal 2019 compared to fiscal 2018 was primarily driven by an increase in employee compensation costs