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:
| Series # | Season # | Title | Directed by | Written by | Original air date | Production code | U.S. viewers (millions) |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 169.0 | 1.0 | "Day 8: 4:00 p.m.– 5:00 p.m." | Brad Turner | Howard Gordon & Evan Katz | January17,2010 | 8AFF01 | 11.50 |
| 171.0 | 3.0 | "Day 8: 6:00 p.m.– 7:00 p.m." | Milan Cheylov | David Fury & Alex Gansa | January18,2010 | 8AFF03 | 10.56 |
| 172.0 | 4.0 | "Day 8: 7:00 p.m.– 8:00 p.m." | Milan Cheylov | Chip Johannessen & Patrick Harbinson | January18,2010 | 8AFF04 | 11.45 |
| 174.0 | 6.0 | "Day 8: 9:00 p.m.– 10:00 p.m." | Brad Turner | Manny Coto & Brannon Braga | February1,2010 | 8AFF06 | 9.76 |
| 175.0 | 7.0 | "Day 8: 10:00 p.m.– 11:00 p.m." | Milan Cheylov | Chip Johannessen & Patrick Harbinson | February8,2010 | 8AFF07 | 10.18 |
| 176.0 | 8.0 | "Day 8: 11:00 p.m.– 12:00 a.m." | Milan Cheylov | David Fury | February15,2010 | 8AFF08 | 8.49 |
| 178.0 | 10.0 | "Day 8: 1:00 a.m.– 2:00 a.m." | Brad Turner | Manny Coto & Brannon Braga | March1,2010 | 8AFF10 | 8.56 |
| 179.0 | 11.0 | "Day 8: 2:00 a.m.– 3:00 a.m." | Nelson McCormick | Evan Katz & David Fury | March8,2010 | 8AFF11 | 8.91 |
| 180.0 | 12.0 | "Day 8: 3:00 a.m.– 4:00 a.m." | Nelson McCormick | Chip Johannessen & Patrick Harbinson | March15,2010 | 8AFF12 | 9.03 |
| 182.0 | 14.0 | "Day 8: 5:00 a.m.– 6:00 a.m." | Milan Cheylov | Story: Evan Katz Teleplay: Alex Gansa | March29,2010 | 8AFF14 | 8.31 |
| 183.0 | 15.0 | "Day 8: 6:00 a.m.– 7:00 a.m." | Brad Turner | Chip Johannessen & Patrick Harbinson | April5,2010 | 8AFF15 | 6.62 |
| 184.0 | 16.0 | "Day 8: 7:00 a.m.– 8:00 a.m." | Brad Turner | Manny Coto & Brannon Braga | April5,2010 | 8AFF16 | 7.90 |
| 185.0 | 17.0 | "Day 8: 8:00 a.m.– 9:00 a.m." | Milan Cheylov | David Fury | April12,2010 | 8AFF17 | 8.33 |
| 186.0 | 18.0 | "Day 8: 9:00 a.m.– 10:00 a.m." | Milan Cheylov | Chip Johannessen & Patrick Harbinson | April19,2010 | 8AFF18 | 8.94 |
| 187.0 | 19.0 | "Day 8: 10:00 a.m.– 11:00 a.m." | Michael Klick | Manny Coto & Brannon Braga | April26,2010 | 8AFF19 | 9.19 |
| 188.0 | 20.0 | "Day 8: 11:00 a.m.– 12:00 p.m." | Michael Klick | Story: Alex Gansa Teleplay: Evan Katz & Alex Gansa | May3,2010 | 8AFF20 | 9.00 |
| 189.0 | 21.0 | "Day 8: 12:00 p.m.– 1:00 p.m." | Milan Cheylov | Chip Johannessen & Patrick Harbinson | May10,2010 | 8AFF21 | 8.51 |
| 190.0 | 22.0 | "Day 8: 1:00 p.m.– 2:00 p.m." | Milan Cheylov | David Fury | May17,2010 | 8AFF22 | 8.98 |
| 191.0 | 23.0 | "Day 8: 2:00 p.m.– 3:00 p.m." | Brad Turner | Shauna McGarry & Geoff Aull | May24,2010 | 8AFF23 | 8.39 |
Question:
How many original airdates did season 20 have?
Answer:
1.0