Table:
|  | Number of shares | Weighed-Average Grant Date Fair Value |
| --- | --- | --- |
|  | (In thousands) |  |
| Non-vested at December 31, 2018 | 17,059 | $19.65 |
| Granted(1) | 9,780 | 12.41 |
| Vested | (9,038) | 19.54 |
| Forfeited | (1,757) | 18.62 |
| Non-vested at December 31, 2019 | 16,044 | 15.42 |
Paragraphs:
Restricted Stock Awards and Restricted Stock Unit Awards
For equity based restricted stock and restricted stock unit awards that contain only service conditions for vesting (time-based awards), we calculate the award fair value based on the closing price of CenturyLink common stock on the accounting grant date. We also grant equity-based awards that contain service conditions as well as additional market or performance conditions. For awards having both service and market conditions, the award fair value is calculated using Monte-Carlo simulations. Awards with service as well as market or performance conditions specify a target number of shares for the award, although each recipient ultimately has the opportunity to receive between 0% and 200% of the target number of shares. For awards with service and market conditions, the percentage received is based on our total shareholder return over the three-year service period versus that of selected peer companies. For awards with service and performance conditions, the percentage received depends upon the attainment of one or more financial performance targets during the two or three-year service period.
The following table summarizes activity involving restricted stock and restricted stock unit awards for the year ended December 31, 2019:
(1) Shares granted whose related performance conditions were not finalized at December 31, 2019, were excluded from this figure.
During 2018, we granted 9.7 million shares of restricted stock and restricted stock unit awards at a weighted-average price of $17.02. During 2017, we granted 5.2 million shares of restricted stock and restricted stock unit awards at a weighted-average price of $22.02. The total fair value of restricted stock that vested during 2019, 2018 and 2017, was $118 million, $169 million and $60 million, respectively.
Question:
How was the award fair value calculated for wards having both service and market conditions?