Table:
|  |  | Year ended December 31, |  |
| --- | --- | --- | --- |
|  | 2019 | 2018 | 2017 |
| Beginning balance | $(1.3) | $(1.9) | $(2.2) |
| Bad debt expense | (1.6) | (0.6) | (0.8) |
| Write-offs, net of recoveries | 1.6 | 1.2 | 1.1 |
| Ending balance | $(1.3) | $(1.3) | $(1.9) |
Paragraphs:
The allowance for doubtful accounts represents management's estimate of uncollectible balances. We determine the allowance based on known troubled accounts, historical experience and other currently available evidence. We write off trade receivables when the likelihood of collection of a trade receivable balance is considered remote.
The rollforward of allowance for doubtful accounts is as follows (in millions):
Question:
What was the percentage change in the ending balance between 2017 and 2018?
Answer: (-1.3-(-1.9))/-1.9 = -31.58