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 | Class | Team | Machine | Points | Rank | Wins |
| --- | --- | --- | --- | --- | --- | --- |
| 1991.0 | 125cc | ELF Kepla-Meiko Honda | RS125 | 55.0 | 13th | 0.0 |
| 1992.0 | 125cc | F.C.C./T.S. Venus- Honda | RS125 | 42.0 | 11th | 0.0 |
| 1993.0 | 125cc | F.C.C. Technical Sports- Honda | RS125 | 266.0 | 2nd | 2.0 |
| 1994.0 | 125cc | Semprucci- Aprilia | RS125R | 224.0 | 1st | 3.0 |
| 1995.0 | 125cc | Team Krona- Aprilia | RS125R | 140.0 | 2nd | 2.0 |
| 1996.0 | 125cc | Aprilia | RS125R | 113.0 | 8th | 0.0 |
| 1997.0 | 125cc | Aprilia | RS125R | 179.0 | 4th | 0.0 |
| 1998.0 | 125cc | Aprilia | RS125R | 229.0 | 1st | 4.0 |
| 1999.0 | 125cc | Honda | RS125 | 56.0 | 14th | 0.0 |
Question:
Which year had a team of Aprilia and a rank of 4th?
Answer:
1997.0