Table:
|  | Service-based RSUs Outstanding |  | Market-based RSUs Outstanding |  |
| --- | --- | --- | --- | --- |
|  | Number of Shares | Weighted-Average Grant Date Fair Value | Number of Shares | Weighted-Average Grant Date Fair Value |
| June 26, 2016 | 3,256,513 | $71.34 | 1,078,591 | $63.12 |
| Granted | 1,224,877 | $114.13 | 435,694 | $111.75 |
| Vested | (1,677,318) | $69.10 | (592,321) | $46.67 |
| Forfeited or canceled | (116,466) | $76.76 | (59,509) | $66.81 |
| June 25, 2017 | 2,687,606 | $92.01 | 862,455 | $83.83 |
| Granted | 964,391 | $183.97 | 285,866 | $170.15 |
| Vested | (1,362,369) | $87.80 | (407,024) | $76.88 |
| Forfeited or canceled | (96,540) | $108.67 | (47,571) | $91.36 |
| June 24, 2018 | 2,193,088 | $134.34 | 693,726 | $104.59 |
| Granted | 893,622 | $161.64 | 163,529 | $165.78 |
| Vested | (1,135,284) | $115.23 | (301,622) | $70.58 |
| Forfeited or canceled | (154,541) | $141.38 | (120,859) | $104.73 |
| June 30, 2019 | 1,796,885 | $159.36 | 434,774 | $144.57 |
Paragraphs:
Restricted Stock Units
During the fiscal years 2019, 2018, and 2017, the Company issued both service-based RSUs and market-based performance RSUs (“PRSUs”). Market-based PRSUs generally vest three years from the grant date if certain performance criteria are achieved and require continued employment. Based upon the terms of such awards, the number of shares that can be earned over the performance periods is based on the Company’s Common Stock price performance compared to the market price performance of the Philadelphia Semiconductor Sector Index (“SOX”), ranging from 0% to 150% of target. The stock price performance or market price performance is measured using the closing price for the 50-trading days prior to the dates the performance period begins and ends. The target number of shares represented by the market-based PRSUs is increased by 2% of target for each 1% that Common Stock price performance exceeds the market price performance of the SOX index. The result of the vesting formula is rounded down to the nearest whole number. Total stockholder return is a measure of stock price appreciation in this performance period.
The following table summarizes restricted stock activity:
The fair value of the Company’s service-based RSUs was calculated based on fair market value of the Company’s stock at the date of grant, discounted for dividends.
Question:
How long do market-based PRSUs usually vest from grant date?
Answer: three years