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 | Model | Length | Width | Fleet Number |
| --- | --- | --- | --- | --- |
| 1970 | GMC T6H4521A | 35' | 96" | 101-103 |
| 1977 | Flxible 35096-6-1 | 31' | 96" | 201-211 |
| 1984 | Orion 01.507 | 36'8" | 96" | 301-303 |
| 19xx | Chance RT52 | 25'11" | 96" | 400's |
| 1993 | Gillig Phantom 3096TB | 30' | 96" | 501-506 |
| 1998 | Gillig Phantom 3096TB | 30' | 96" | 603 |
| 1999 | Chance RT52 | 25'11" | 96" | 701-705 |
Question:
What is fleet number for the year of 19xx?
Answer:
400's