Table:
|  |  | Years Ended December 31, |  |
| --- | --- | --- | --- |
|  | 2019 | 2018 | 2017 |
| Balances at beginning of period | $2,084 | $2,312 | $2,329 |
| Warranty acquired in business combinations | 4,818 | 305 | 118 |
| Increases to accruals | 1,752 | 1,606 | 2,029 |
| Warranty expenditures | (2,249) | (2,127) | (2,184) |
| Effect of changes in exchange rates | 8 | (12) | 20 |
| Balances at end of period | $6,413 | $2,084 | $2,312 |
Paragraphs:
ADVANCED ENERGY INDUSTRIES, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – (continued) (in thousands, except per share amounts)
NOTE 15. WARRANTIES
Provisions of our sales agreements include customary product warranties, ranging from 12 months to 24 months following installation. The estimated cost of our warranty obligation is recorded when revenue is recognized and is based upon our historical experience by product, configuration and geographic region.
Our estimated warranty obligation is included in Other accrued expenses in our Consolidated Balance Sheets. Changes in our product warranty obligation are as follows:
Question:
What are the years included in the table for Changes in our product warranty obligation
Answer: 2019, 2018, 2017