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:
| Season | Winners | Total wins | Runners-up | Third-place | Number of clubs |
| --- | --- | --- | --- | --- | --- |
| 1987.0 | Liaoning | 1.0 | Tianjin | Shanghai | 8.0 |
| 1988.0 | Liaoning | 2.0 | Shandong | Shanghai | 21.0 |
| 1989.0 | China B | 1.0 | Liaoning | Shanghai | 8.0 |
| 1990.0 | Liaoning | 3.0 | August 1st | Dalian | 8.0 |
| 1991.0 | Liaoning | 4.0 | Shanghai | Beijing | 8.0 |
| 1992.0 | Liaoning | 5.0 | Guangzhou FC | Dalian | 8.0 |
| 1993.0 | Liaoning | 6.0 | Guangdong | Beijing | 8.0 |
Question:
What is the sum of the season with 8 clubs and shanghai as the runners-up?
Answer:
1991.0