Table:
|  | Number of shares | Weighted average exercise price | Weighted average remaining contractual term | Aggregate Intrinsic Value (in thousands) |
| --- | --- | --- | --- | --- |
| Outstanding at September 30, 2017 | 9,376 | 4.49 | - | - |
| Granted | - | - | - | - |
| Expired | (1,250) | 6.82 | - | - |
| Forfeited | - | - | - | - |
| Exercised | (4,626) | 4.67 | - | - |
| Outstanding at September 30, 2018 | 3,500 | $3.42 | - | - |
| Granted | - | - | - | - |
| Expired | (500) | $2.99 | - | - |
| Forfeited | - | - | - | - |
| Exercised | (1,000) | 2.99 | - | - |
| Outstanding at September 30, 2019 | 2,000 | $3.75 | .98 years | $19 |
| Exercisable at September 30, 2019 | 2,000 | $3.75 | .98 years | $19 |
| Vested and expected to vest at September 30, 2019 | 2,000 | $3.75 | .98 years | $19 |
Paragraphs:
As stock-based compensation expense recognized in the consolidated statements of operations is based on awards ultimately expected to vest, expense for grants beginning upon adoption on October 1, 2005 has been reduced for estimated forfeitures. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. The forfeiture rates for the years ended September 30, 2019 and 2018 were based on actual forfeitures.
No cash was used to settle equity instruments granted under share-base payment arrangements in any of the years in the two-year period ended September 30, 2019.
The following tables provide summary data of stock option award activity:
Question:
What is the percentage of outstanding shares as at September 30, 2019 expired between September 30, 2018 and 2019?
Answer: 500/2000  = 25