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 | Original air date | Production Code | U.S. viewers (millions) |
| --- | --- | --- | --- | --- | --- |
| 21.0 | 1.0 | "A Doomed Christmas" | December10,2011 | 121.0 | N/A |
| 22.0 | 2.0 | "Big Dog on Campus / Dog's Best Friend" | January16,2012 | 122.0 | N/A |
| 23.0 | 3.0 | "Monkey Business / Diary of a Mad Cat" | April21,2012 | 125.0 | N/A |
| 24.0 | 4.0 | "Dudley Do-Wrong / Puppy Unplugged" | May6,2012 | 123.0 | N/A |
| 25.0 | 5.0 | "Freaky Spy Day / Dog Tired" | May 13, 2012 | 202.0 | N/A |
| 26.0 | 6.0 | "Top Dog / Quack in the Box" | May20,2012 | 124.0 | N/A |
| 27.0 | 7.0 | "Lie Like A Dog / Cold Fish" | May27,2012 | 126.0 | 2.3 |
| 28.0 | 8.0 | "Pup Daddy / Candy Cane-ine" | June 3, 2012 | 201.0 | N/A |
| 29.0 | 9.0 | "Bark to the Future / Lights, Camera, Quacktion" | October 13, 2012 | 205.0 | 1.8 |
| 30.0 | 10.0 | "Happy Howl-O-Ween" | October 27, 2012 | 210.0 | 1.6 |
| 31.0 | 11.0 | "Bark to Nature / Mutts and Bolts" | August 5, 2013 | 213.0 | 1.9 |
| 32.0 | 12.0 | "Dog House / Time Waits for No Mutt" | August 6, 2013 | 203.0 | 1.6 |
| 33.0 | 13.0 | "Hush Puppy / Quacky Birthday" | August8,2013 | 209.0 | 1.8 |
| 34.0 | 14.0 | "Love Bird / Bluff Puppy" | October20,2013 (Nicktoons) | 204.0 | N/A |
| 35.0 | 15.0 | "Rat Trap / Agent of the Year" | October27,2013 (Nicktoons) | 207.0 | N/A |
| 36.0 | 16.0 | "Barking Tall / Bad Eggs" | November3,2013 (Nicktoons) | 212.0 | N/A |
| 37.0 | 17.0 | "Carbon Copies / TUFF Cookies" | November10,2013 (Nicktoons) | 214.0 | N/A |
| 39.0 | 19.0 | "T.U.F.F. Choices / Sob Story" | TBA (Nicktoons) | 208.0 | N/A |
Question:
How many millions of US viewers watched the episode titled "Happy Howl-o-ween"?
Answer:
1.6