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:
| Rank | Name | Height | Floors | Year | Notes |
| --- | --- | --- | --- | --- | --- |
| 1 | Zions Bank Building\n\n\n\n\nZions Bank Building in Downtown Boise, Idaho | 323 ft (98 m) | 20 | 2013 | Tallest building in state since 2013. |
| 2 | Boise Airport Air Traffic Control Tower | 295 ft (90 m) |  | 2009 | Tallest ATC tower in the Northwest. |
| 3 | US Bank Plaza\n\n\n\n\nUS Bank Building in Downtown Boise | 267 ft (81 m) | 19 | 1978 | Tallest building in state from 1978 to 2013.\n"Idaho First Plaza" until 1989. |
| 3 | One Capital Center\n\n\n\n\nOne Capital Center in Downtown Boise, Idaho | 206 ft (63 m) | 14 | 1975 | Tallest building in Boise\nfrom 1975 to 1978. |
| 4 | Idaho State Capitol\n\n\n\n\nIdaho State Capitol; Boise, Idaho | 198 ft (60 m) | 4 | 1920 | Tallest building in Boise\nfrom 1920 to 1975. |
| 5 | The Grove Hotel\n\n\n\n\nGrove Hotel in Downtown Boise, Idaho | 196 ft (60 m) | 16 | 2000 |  |
| 6 | The Aspen\n\n\n\n\nAspen Loft Building in Downtown Boise, Idaho | 194 ft (59 m) | 17 | 2009 |  |
| 7 | Wells Fargo Building\n\n\n\n\nWells Fargo Building in Downtown Boise, Idaho | 182 ft (55 m) | 11 | 1988 | First Interstate until 1996 |
| 8 | Banner Bank Building\n\n\n\n\nBanner Bank Building in Downtown Boise, Idaho | 181 ft (55 m) | 11 | 2006 |  |
| 9 | Key Tower\n\n\n\n\nKey Bank Building in Downtown Boise, Idaho | 174 ft (53 m) | 13 | 1963 | Bank of Idaho until 1981,\nFirst Interstate until 1988 |
| 10 | Bronco Stadium\n\n\n\n\nBronco stadium in Boise, Idaho | 170 ft (52 m) |  | 1970 |  |
| 11 | Hoff Building\n\n\n\n\nHoff Building in Downtown Boise, Idaho | 165 ft (50 m) | 14 | 1930 |  |
| 12 | Chase Tower Plaza\n\n\n\n\nChase Building in Downtown Boise, Idaho | 160 ft (49 m) | 11 | 1995 | Washington Mutual until 2009 |
| 13 | Idaho Power Building\n\n\n\n\nIdaho Power Building in Downtown Boise, Idaho | 160 ft (49 m) | 9 | 1990 |  |
Question:
what is the number of floors of the oldest building?
Answer:
4