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:
| No. in series | No. in season | Title | Directed by | Written by | Original air date | U.S. viewers (millions) |
| --- | --- | --- | --- | --- | --- | --- |
| 98.0 | 1.0 | "Rio" (Part 4) | Joe Chappelle | Sunil Nayar | September18,2006 | 17.62 |
| 99.0 | 2.0 | "Going Under" | Matt Earl Beesley | Marc Dube & John Haynes | September25,2006 | 17.79 |
| 100.0 | 3.0 | "Death Pool 100" | Sam Hill | Ann Donahue & Elizabeth Devine | October2,2006 | 17.90 |
| 101.0 | 4.0 | "If Looks Could Kill" | Scott Lautanen | Ildy Modrovich & Barry O'Brien | October9,2006 | 17.60 |
| 102.0 | 5.0 | "Death Eminent" | Eagle Egilsson | Corey Miller & Brian Davidson | October16,2006 | 18.12 |
| 103.0 | 6.0 | "Curse of the Coffin" | Joe Chappelle | Sunil Nayar & Krystal Houghton | October23,2006 | 17.83 |
| 104.0 | 7.0 | "High Octane" | Sam Hill | Marc Dube | November6,2006 | 16.80 |
| 105.0 | 8.0 | "Darkroom" | Karen Gaviola | John Haynes | November13,2006 | 18.77 |
| 106.0 | 9.0 | "Going Going Gone" | Matt Earl Beesley | Elizabeth Devine | November20,2006 | 18.54 |
| 107.0 | 10.0 | "Come As You Are" | Joe Chappelle | Brian Davidson | November27,2006 | 17.13 |
| 108.0 | 11.0 | "Backstabbers" | Gina Lamar | Barry O'Brien | December11,2006 | 16.00 |
| 109.0 | 12.0 | "Internal Affairs" | Scott Lautanen | Corey Miller | January8,2007 | 16.01 |
| 110.0 | 13.0 | "Throwing Heat" | Joe Chappelle | Krystal Houghton | January22,2007 | 18.85 |
| 111.0 | 14.0 | "No Man's Land" (Part 1) | Scott Lautanen | Dominic Abeyta | February5,2007 | 18.43 |
| 112.0 | 15.0 | "Man Down" (Part 2) | Karen Gaviola | Ildy Modrovich | February12,2007 | 19.90 |
| 113.0 | 16.0 | "Broken Home" | Sam Hill | Barry O'Brien & Krystal Houghton | February19,2007 | 19.23 |
| 114.0 | 17.0 | "A Grizzly Murder" | Eagle Egilsson | Elizabeth Devine & Brian Davidson | February26,2007 | 17.42 |
| 115.0 | 18.0 | "Triple Threat" | Scott Lautanen | Corey Miller & Sunil Nayar | March19,2007 | 17.66 |
| 116.0 | 19.0 | "Bloodline" | Carey Meyer | John Haynes & Marc Dube | April9,2007 | 16.11 |
| 117.0 | 20.0 | "Rush" | Sam Hill | Ildy Modrovich & Krystal Houghton | April16,2007 | 15.36 |
| 118.0 | 21.0 | "Just Murdered" | Eagle Egilsson | Ty Scott | April23,2007 | 17.03 |
| 119.0 | 22.0 | "Burned" | Anthony Hemingway | Corey Evett & Matt Partney | April30,2007 | 17.24 |
| 120.0 | 23.0 | "Kill Switch" | Scott Lautanen | Corey Miller & Marc Dube | May7,2007 | 17.18 |
Question:
How many millions of viewers watched episode 15?
Answer:
19.9