Table:
|  | December 31, 2019 | December 31, 2018 |
| --- | --- | --- |
|  | (in thousands) |  |
| Debt principal | $460,000 | $460,000 |
| Unamortized discount | 65,313 | 80,019 |
| Net carrying amount of convertible debt | $394,687 | $379,981 |
Paragraphs:
The below tables represents the key components of Teradyne’s convertible senior notes:
As of December 31, 2019, the unamortized discount was $65.3 million, which will be amortized over four years using the effective interest rate method. The carrying amount of the equity component was $100.8 million. As of December 31, 2019, the conversion price was approximately $31.62 per share and if converted the value of the notes was $992.0 million.
Question:
What was the percentage change in Debt principal from 2018 to 2019?
Answer: (460000-460000)/460000 = 0