to produce the show. Broadcast SpongeBob SquarePants was Nickelodeon's first original Saturday-morning cartoon. It first aired as a preview on May 1, 1999, and officially premiered on July 17 of the same year. Hillenburg noted that the show's premise "is that innocence prevailswhich I don't think it always does in real life." It has received positive reviews from critics, and has been noted for its appeal to different age groups. James Poniewozik of Time magazine described the titular character as "the anti-Bart Simpson, temperamentally and physically: his head is as squared-off and neat as Bart's is unruly, and he has a personality to matchconscientious, optimistic and blind to the faults in the world and those around him." On the other hand, The New York Times critic Joyce Millman said that the show "is clever without being impenetrable to young viewers and goofy without boring grown-ups to tears. It's the most charming toon on television, and one of the weirdest. ...Like Pee-wee's Playhouse, SpongeBob joyfully dances on the fine line between childhood and adulthood, guilelessness and camp, the warped and the sweet." SpongeBob SquarePants was an immediate hit. Within its first month on air, it overtook Pokémon (1997) as the highest-rated Saturday morning children's series. By the end of 2001, the show boasted the highest ratings of any children's series on television. Nickelodeon began adding SpongeBob SquarePants to its Monday-through-Thursday prime-time block. This programming change increased the number of older viewers significantly. By May 2002, the show's total viewership reached more than 61 million, 20 million of which were aged 18 to 49. Hillenburg did not expect the show would be very popular even to adults: "I never imagined that it would get to this point. When you set out to do a show about a sponge, you can't anticipate this kind of craze. We just try to make ourselves laugh, then ask if it's appropriate for children. I can tell you that we hoped it would be liked by adults. But we really thought the best we could hope for was a college audience." SpongeBob SquarePants has gone on to become one of the longest-running series on Nickelodeon. "Ten years. I never imagined working on the show to this date and this long. It never was possible to conceive that. ...I really figured we might get a season and a cult following, and that might be it," Hillenburg said in