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\nft (m) | Floors | Year | Coordinates | Notes |
| --- | --- | --- | --- | --- | --- | --- |
| 1 | Ordway Building | 404 (123) | 28 | 1970 | 37°48′36″N 122°15′51″W﻿ / ﻿37.81000°N 122.26417°W | Tallest building in both Oakland and in the Bay Area outside of San Francisco; tallest building constructed in the 1970s |
| 2 | Kaiser Center | 390 (119) | 28 | 1960 | 37°48′32″N 122°15′52″W﻿ / ﻿37.80889°N 122.26444°W | Tallest building constructed in the 1960s |
| 3 | Lake Merritt Plaza | 371 (113) | 27 | 1988 | 37°48′27″N 122°15′54″W﻿ / ﻿37.80750°N 122.26500°W | Tallest building constructed in the 1980s |
| 4 | 1111 Broadway | 360 (110) | 24 | 1990 | 37°48′10″N 122°16′22″W﻿ / ﻿37.80278°N 122.27278°W | Tallest building constructed in the 1990s |
| 5 | Kaiser Engineering Building | 336 (102) | 25 | 1984 | 37°48′21″N 122°15′54″W﻿ / ﻿37.80583°N 122.26500°W |  |
| 6 | Clorox Building | 330 (101) | 24 | 1976 | 37°48′12″N 122°16′20″W﻿ / ﻿37.80333°N 122.27222°W |  |
| 7= | EM Harris State Office Building | 328 (100) | 22 | 1998 | 37°48′23″N 122°16′24″W﻿ / ﻿37.80639°N 122.27333°W |  |
| 7= | Ronald V. Dellums Federal Building South | 328 (100) | 18 | 1994 | 37°48′16″N 122°16′29″W﻿ / ﻿37.80444°N 122.27472°W |  |
| 7= | Ronald V. Dellums Federal Building North | 328 (100) | 18 | 1994 | 37°48′18″N 122°16′28″W﻿ / ﻿37.80500°N 122.27444°W |  |
| 10 | Oakland City Hall | 320 (98) | 14 | 1914 | 37°48′19″N 122°16′21″W﻿ / ﻿37.80528°N 122.27250°W | Tallest building constructed in the 1910s; National Register of Historic Places |
| 11 | Tribune Tower | 310 (94) | 22 | 1906 | 37°48′11″N 122°16′14″W﻿ / ﻿37.80306°N 122.27056°W | Tallest building constructed in the 1920s |
| 12 | 1330 Broadway | 297 (91) | 21 | 1956–1959 | 37°48′14″N 122°16′14″W﻿ / ﻿37.80389°N 122.27056°W |  |
| 13 | Pacific Bell Building | 296 (90) | 20 | 1985 | 37°48′37″N 122°15′57″W﻿ / ﻿37.81028°N 122.26583°W |  |
| 14 | 555 City Center | 279 (85) | 20 | 2002 | 37°48′13″N 122°16′31″W﻿ / ﻿37.80361°N 122.27528°W |  |
| 15 | Park Bellevue Tower | 270 (82) | 25 | 1969 | 37°48′28″N 122°15′20″W﻿ / ﻿37.80778°N 122.25556°W |  |
| 16 | St. Paul's Towers | 267 (81) | 22 | 1966 | 37°48′42″N 122°15′37″W﻿ / ﻿37.81167°N 122.26028°W |  |
| 17 | The Grand Apartments | 263 (80) | 22 | 2008 | 37°48′41″N 122°15′53″W﻿ / ﻿37.81139°N 122.26472°W |  |
| 18 | Central Building | 235 (72) | 15 | 1926 | 37°48′15″N 122°16′14″W﻿ / ﻿37.80417°N 122.27056°W |  |
| 19 | Bank of America Building | 225 (69) | 18 | 1907 | 37°48′10″N 122°16′17″W﻿ / ﻿37.80278°N 122.27139°W | Tallest building constructed in the decade of 1900 |
| 20 | Financial Center Building | 214 (65) | 14 | 1929 | 37°48′13″N 122°16′13″W﻿ / ﻿37.80361°N 122.27028°W |  |
| 21 | SBC Building | 203 (62) | 15 | — | 37°48′21″N 122°16′08″W﻿ / ﻿37.80583°N 122.26889°W |  |
Question:
how many of the tallest buildings in oakland were built before 1950?
Answer:
5