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:
| Class | Quantity | Type | Delivered | K.B.Sts.B. Class | Retired |
| --- | --- | --- | --- | --- | --- |
| A | 24.0 | 2A n2 | 1857-59 | B IX* | 1902-08 |
| B | 66.0 | 1B n2 | 1858-66 | B V | 1900-11 |
| B | 19.0 | 1B n2 | 1873-75 | B IX | 1907-12 |
| C | 12.0 | C n2 | 1862-63 | C II | 1899-06 |
| C | 52.0 | C n2 | 1867-75 | C III | 1921-24 |
| D | 14.0 | B n2t | 1866-71 | D II | 1895-24 |
| E | 2.0 | B n2 | 1869 | B V | 1900-08 |
Question:
What is the lowest quantity of the 1b n2 type, which was retired in 1907-12?
Answer:
19.0