Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Year | Car number | Start | Qual. speed | Speed rank | Finish | Laps completed | Laps led | Race status | Chassis |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1963.0 | 92.0 | 5.0 | 149.750 | 7.0 | 2.0 | 200.0 | 28.0 | Running | Lotus-Ford 29/3 |
| 1964.0 | 6.0 | 1.0 | 158.828 | 1.0 | 24.0 | 47.0 | 14.0 | Suspension | Lotus-Ford 34/3 |
| 1965.0 | 82.0 | 2.0 | 160.729 | 2.0 | 1.0 | 200.0 | 190.0 | Running | Lotus-Ford 38/1 |
| 1966.0 | 19.0 | 2.0 | 164.114 | 2.0 | 2.0 | 200.0 | 66.0 | Running | Lotus-Ford 38/4 |
| 1967.0 | 31.0 | 16.0 | 163.213 | 23.0 | 31.0 | 35.0 | 0.0 | Piston | Lotus-Ford 38/7 |
Question:
What year(s) was the race status piston?
Answer:
1967.0