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 | Manufacturer | Model | Length (ft.) | Fuel or Propulsion | Fleet series | Quantity |
| --- | --- | --- | --- | --- | --- | --- |
| 2002.0 | Thomas Dennis | SLF-230 | 30' | Diesel | 917–921 | 5.0 |
| 2003.0 | Orion | V (05.503) | 30' | Diesel | 922–928 | 7.0 |
| 2005.0 | Orion | V (05.503) | 30' | Diesel | 060–066 | 7.0 |
| 2010.0 | Gillig | Advantage Low Floor | 30' | Diesel | 981–986 | 6.0 |
| 2011.0 | Gillig | Advantage Low Floor HEV | 35' | Hybrid | 157–158 | 2.0 |
Question:
Name the sum of quantity for before 2011 model slf-230
Answer:
5.0