Table:
|  |  | Year Ended December 31, |  |
| --- | --- | --- | --- |
|  | 2019 | 2018 | 2017 |
| Depreciation expense | $2,540 | $2,320 | $2,149 |
| Amortization expense | 4,764 | 2,158 | 1,834 |
| Impairment losses | — | 19 | 78 |
Paragraphs:
GreenSky, Inc. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS — (Continued) (United States Dollars in thousands, except per share data, unless otherwise stated)
Note 6. Property, Equipment and Software
The following table shows depreciation and amortization expense, as well as recorded impairment losses related to abandoned capitalized software projects that are recorded within general and administrative expense in the Consolidated Statements of Operations. We determined that these software projects would not generate future cash flows through use or disposal to a third party and, as such, the fair value as of the respective reporting dates was $0.
Question:
How many years did depreciation expense exceed $2,000 thousand?