Table:
|  | Number of Shares | Weighted-Average Grant-Date |
| --- | --- | --- |
|  | (in thousands) | Fair Value per Share |
| Outstanding at December 31, 2018 | 3,263 | $20.23 |
| Granted | 1,580 | 23.23 |
| Vested | (1,541) | 20.16 |
| Canceled | (378) | 21.52 |
| Outstanding at December 31, 2019 | 2,924 | 21.72 |
Paragraphs:
Restricted Stock Units
A summary of the Company’s restricted stock unit activity is as follows:
Performance-Based Restricted Stock Units
Performance-based restricted stock units are eligible to vest at the end of each fiscal year in a three-year performance period based on the Company’s annual growth rate in net sales and non-GAAP diluted earnings per share (subject to certain adjustments) over a multiple of four times the related results for the fourth quarter of 2018 relative to the growth rates for a peer group of companies for the same metrics and periods.
For the performance-based restricted stock units granted in 2019, 60% of each performance-based award is subject to the net sales metric for the performance period and 40% is subject to the non-GAAP diluted earnings per share metric for the performance period. The maximum percentage for a particular metric is2 50% of the target number of units subject to the award related to that metric, however, vesting of the performance stock units is capped at 30% and 100%, respectively, of the target number of units subject to the award in years one and two, respectively, of the three-year performance period.
As of December 31, 2019, the Company believes that it is probable that the Company will achieve performance metrics specified in the award agreement based on its expected revenue and non-GAAP diluted EPS results over the performance period and calculated growth rates relative to its peers’ expected results based on data available, as defined in the award agreement.
Question:
What is the eligibility of Performance-based restricted stock to vest?
Answer: at the end of each fiscal year in a three-year performance period based on the Company’s annual growth rate