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 |
| --- | --- | --- | --- | --- |
| 1951.0 | Scuderia Milano | Maserati 4CLT/48 | Maserati Straight-4 | 0.0 |
| 1954.0 | Officine Alfieri Maserati | Maserati 250F | Maserati Straight-6 | 0.0 |
| 1956.0 | Officine Alfieri Maserati | Maserati 250F | Maserati Straight-6 | 6.0 |
| 1957.0 | Francesco Godia Sales | Maserati 250F | Maserati Straight-6 | 0.0 |
| 1958.0 | Francesco Godia Sales | Maserati 250F | Maserati Straight-6 | 0.0 |
Question:
What is the average year of an entrant that had fewer than 6 points and a Maserati Straight-6 engine?
Answer:
1956.3333333333333