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 | Entrant | Chassis | Engine | Points |
| --- | --- | --- | --- | --- |
| 1963.0 | Ecurie Maarsbergen | Porsche 718 | Porsche Flat-4 | 3.0 |
| 1964.0 | Team Lotus | Lotus 25 | Climax V8 | 0.0 |
| 1965.0 | Team Lotus | Lotus 25 | Climax V8 | 0.0 |
| 1966.0 | Ron Harris / Team Lotus | Lotus 44 F2 | Cosworth Straight-4 | 0.0 |
| 1967.0 | Gerhard Mitter | Brabham BT23 F2 | Cosworth Straight-4 | 0.0 |
| 1969.0 | BMW | BMW 269 F2 | BMW Straight-4 | 0.0 |
Question:
What is the average Year when there was a cosworth straight-4 engine, and the Entrant was ron harris / team lotus?
Answer:
1966.0