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 | Production code |
| --- | --- | --- | --- | --- | --- | --- |
| 78.0 | 1.0 | " Blood Ties (Part 1)" | Alan Taylor | Anya Epstein | October17,1997 | 601.0 |
| 79.0 | 2.0 | " Blood Ties (Part 2)" | Nick Gomez | David Simon | October24,1997 | 602.0 |
| 80.0 | 3.0 | " Blood Ties (Part 3)" | Mark Pellington | David Simon & Anya Epstein | October31,1997 | 603.0 |
| 81.0 | 4.0 | " Subway " | Gary Fleder | James Yoshimura | December5,1997 | 604.0 |
| 82.0 | 5.0 | "Baby, It's You" | Ed Sherin | Jorge Zamacona | November14,1997 | 605.0 |
| 83.0 | 6.0 | "Birthday" | Alison Maclean | Julie Martin | November7,1997 | 606.0 |
| 84.0 | 7.0 | "Saigon Rose" | Nick Gomez | Eric Overmeyer | November21,1997 | 607.0 |
| 85.0 | 8.0 | "All Is Bright" | Matt Reeves | Rafael Alvarez | December12,1997 | 608.0 |
| 86.0 | 9.0 | "Closet Cases" | Leslie Libman & Larry Williams | Christopher Kyle | January2,1998 | 609.0 |
| 87.0 | 10.0 | "Sins of the Father" | Mary Harron | Darryl LeMont Wharton | January9,1998 | 610.0 |
| 88.0 | 11.0 | "Shaggy Dog, City Goat" | Kyle Secor | Eric Overmeyer | January16,1998 | 611.0 |
| 89.0 | 12.0 | "Something Sacred (Part 1)" | Uli Edel | Anya Epstein | January30,1998 | 612.0 |
| 90.0 | 13.0 | "Something Sacred (Part 2)" | Uli Edel | David Simon | January30,1998 | 613.0 |
| 91.0 | 14.0 | "Lies and Other Truths" | Nick Gomez | Noel Behn | March6,1998 | 614.0 |
| 92.0 | 15.0 | "Pit Bull Sessions" | Barbara Kopple | Sean Whitesell | March13,1998 | 615.0 |
| 93.0 | 16.0 | "Mercy" | Alan Taylor | Eric Overmeyer | March20,1998 | 616.0 |
| 94.0 | 17.0 | "Abduction" | Kenneth Fink | Julie Martin | March27,1998 | 617.0 |
| 95.0 | 18.0 | "Full Court Press" | Clark Johnson | Phillip B. Epstein | April3,1998 | 618.0 |
| 96.0 | 19.0 | "Strangled, Not Stirred" | Jay Tobias | Linda McGibney | April10,1998 | 619.0 |
| 97.0 | 20.0 | "Secrets" | Ed Bianchi | Yaphet Kotto | April17,1998 | 620.0 |
| 98.0 | 21.0 | " Finnegan's Wake " | Steve Buscemi | David Mills | April24,1998 | 621.0 |
| 99.0 | 22.0 | " Fallen Heroes (Part 1)" | Kathryn Bigelow | Lois Johnson | May1,1998 | 622.0 |
Question:
When did "secrets" air?
Answer:
April17,1998