Question: In what year did this pilot episode air of this American animated television series, whose title character held the same name as the show and also included the character Mrs. Puff?

full_context: Document 1: List of SpongeBob SquarePants cast members: "SpongeBob SquarePants" is an American animated television series created by marine biologist and animator Stephen Hillenburg that debuted on Nickelodeon in the United States on May 1, 1999. The regular voice cast consists of Tom Kenny, Clancy Brown, Rodger Bumpass, Bill Fagerbakke, Mr. Lawrence, Jill Talley, Carolyn Lawrence, Mary Jo Catlett and Lori Alan. Most one-off and background characters are voiced by Dee Bradley Baker, Sirena Irwin, Bob Joles, Mark Fite and Thomas F. Wilson. Throughout the show's run, it has employed numerous guest stars from many ranges of professions. Repeat guests include Ernest Borgnine, Tim Conway, Brian Doyle-Murray, Marion Ross, John O'Hurley and Michael McKean.
Document 2: SpongeBob SquarePants (season 1): The first season of the American animated television sitcom "SpongeBob SquarePants", created by former marine biologist and animator Stephen Hillenburg, aired from May 1, 1999 to April 8, 2000, and consists of 20 episodes. The series chronicles the exploits and adventures of the title character and his various friends in the fictional underwater city of Bikini Bottom. The show features the voices of Tom Kenny, Bill Fagerbakke, Rodger Bumpass, Clancy Brown, Mr. Lawrence, Jill Talley, Carolyn Lawrence, Mary Jo Catlett, and Lori Alan. Among the first guest stars to appear on the show were Ernest Borgnine and Tim Conway voicing the superhero characters of Mermaid Man and Barnacle Boy, respectively.
Document 3: Pearl Krabs: Pearl Krabs is a fictional character in the American animated television series "SpongeBob SquarePants". She is voiced by actress Lori Alan and first appeared in the season one episode "Squeaky Boots" on September 4, 1999. She was created by marine biologist and animator Stephen Hillenburg, who was inspired to design a whale character while supervising whale watches at the Orange County Marine Institute in Dana Point, California.
Document 4: SpongeBob SquarePants: SpongeBob SquarePants is an American animated television series created by marine biologist and animator Stephen Hillenburg for Nickelodeon. The series chronicles the adventures and endeavors of the title character and his various friends in the fictional underwater city of Bikini Bottom. The series' popularity has made it a media franchise, as well as the highest rated series to ever air on Nickelodeon, and the most distributed property of MTV Networks. As of 2015, the media franchise has generated $12 billion in merchandising revenue for Nickelodeon.
Document 5: SpongeBob SquarePants: Original Theme Highlights: SpongeBob SquarePants: Original Theme Highlights is the first album of songs played on the Nickelodeon TV series "SpongeBob SquarePants". It includes tracks sung by the cartoon's characters: SpongeBob SquarePants, Sandy Cheeks, Patrick Star, Squidward Tentacles, and Plankton. Its total running time is 9 minutes and 9 seconds, spanning seven tracks.
Document 6: Mary Jo Catlett: Mary Jo Catlett (born September 2, 1938) is an American actress. She is notable for her role as housekeeper Pearl Gallagher on the television sitcom "Diff'rent Strokes", and currently for her role as Mrs. Puff in "SpongeBob SquarePants", which she has held since the show's debut.
Document 7: Patrick Star: Patrick Star is a fictional character in the American animated television series "SpongeBob SquarePants". He is voiced by actor Bill Fagerbakke, who also voices numerous other characters on the show. Created and designed by marine biologist and cartoonist Stephen Hillenburg, the series creator, Patrick first appeared on television in the show's pilot episode "Help Wanted" on May 1, 1999.
Document 8: List of SpongeBob SquarePants guest stars: In addition to the show's regular cast of voice actors, guest stars have been featured on "SpongeBob SquarePants", an American animated television series created by marine biologist and animator Stephen Hillenburg for Nickelodeon. "SpongeBob SquarePants" chronicles the adventures and endeavors of the title character and his various friends in the fictional underwater city of Bikini Bottom. Many of the ideas for the show originated in an unpublished, educational comic book titled "The Intertidal Zone", which Hillenburg created in the mid-1980s. He began developing "SpongeBob SquarePants" into a television series in 1996 upon the cancellation of "Rocko's Modern Life", which Hillenburg directed. The pilot episode first aired on Nickelodeon in the United States on May 1, 1999. The show's ninth season premiered in 2012, and episodes of "SpongeBob SquarePants" have aired. A feature-length film adaptation of the show, "The SpongeBob SquarePants Movie", was released in 2004; in 2015, a sequel, "", was released.
Document 9: Mrs. Puff: Mrs. Puff is a fictional character in the American animated television series "SpongeBob SquarePants" and both films based on the franchise. She is voiced by actress Mary Jo Catlett and debuted in the season one episode "Boating School" on August 7, 1999. Mrs. Puff was created and designed by marine biologist and animator Stephen Hillenburg. He developed the character in response to a request from Nickelodeon that the show star a schoolteacher. Hillenburg did not want to write SpongeBob as a school-age child, so Mrs. Puff was introduced as his driving instructor rather than a classroom educator.
Document 10: List of SpongeBob SquarePants characters: The characters in the American animated television series "SpongeBob SquarePants" were created by artist, animator, and former marine biologist Stephen Hillenburg. In addition to the series' main cast, various celebrities have voiced roles in "SpongeBob SquarePants". Notably, Ernest Borgnine and Tim Conway voice the roles of recurring characters Mermaid Man and Barnacle Boy respectively (Joe Whyte assumed the role of Mermaid Man shortly after Ernest Borgnine's death in 2012), while others have taken a cameo part.
Document 11: Help Wanted (SpongeBob SquarePants): "Help Wanted" is the pilot episode of the American animated television series "SpongeBob SquarePants". It originally aired on Nickelodeon in the United States on May 1, 1999, following the television airing of the 1999 Kids' Choice Awards. The episode follows the protagonist, an anthropomorphic sea sponge named SpongeBob SquarePants, attempting to get a job at a local restaurant called the Krusty Krab. However, he is tasked to find a seemingly non-existent high-caliber spatula because the owner, Mr. Krabs, considers him unqualified for the position. Eventually, crowds of ravenous anchovies stop by the Krusty Krab and demand meals. SpongeBob returns from his errand, having fulfilled the request of Mr. Krabs and found a mechanical spatula. He utilizes the spatula to fulfill the anchovies' hunger. SpongeBob is then welcomed by Mr. Krabs as a Krusty Krab employee.
Document 12: SpongeBob SquarePants (character): SpongeBob SquarePants is the titular character and protagonist of the American animated television series of the same name. He is voiced by actor and comedian Tom Kenny and first appeared on television in the series' pilot episode on May 1, 1999.
Document 13: SpongeBob SquarePants (film series): SpongeBob SquarePants is an American animated/live-action comedy film series based on the Nickelodeon animated television program of the same name, created by Stephen Hillenburg. It began in 2004 with the release of "The SpongeBob SquarePants Movie". The series is distributed and owned by Paramount Pictures, a subsidiary of Nickelodeon's parent company Viacom. All films feature the regular television voice cast: Tom Kenny, Clancy Brown, Rodger Bumpass, Bill Fagerbakke, Mr. Lawrence, Jill Talley, Carolyn Lawrence, Mary Jo Catlett and Lori Alan. The first installment was directed by Hillenburg, and all subsequent films were directed by former showrunner Paul Tibbitt.
Document 14: Squidward Tentacles: Squidward Quincy Tentacles is a fictional character voiced by actor Rodger Bumpass in the American animated comedy television series "SpongeBob SquarePants". Squidward was created and designed by marine biologist and animator Stephen Hillenburg. He first appeared on television in the series' pilot episode "Help Wanted" on May 1, 1999.
Document 15: List of SpongeBob SquarePants episodes: "SpongeBob SquarePants" is an American animated television series created by marine biologist and animator Stephen Hillenburg for Nickelodeon. The series is set in the fictional underwater city of Bikini Bottom, and centers on the adventures and endeavors of SpongeBob SquarePants, an over-optimistic sea sponge that annoys other characters. Many of the ideas for the show originated in an unpublished, educational comic book titled "The Intertidal Zone", which Hillenburg created in the mid-1980s. He began developing "SpongeBob SquarePants" into a television series in 1996 after the cancellation of "Rocko's Modern Life", another Nickelodeon television series which Hillenburg previously directed.
ground_truth: May 1, 1999