Conversation so far:
What did Stephen Hillenburg start Stephen Hillenburg's career in?
park service attendant in Utah and an art director in San Francisco, before landing the job he wanted: teaching children.
What subject did he teach when he became a teacher?
marine-biology teacher.
Did he teach any other subjects alone the years?
tide-pool ecology, nautical history, diversity and adaptation.
Between those years did he come up with Sponge bob?
CANNOTANSWER.

Question: What year was he teaching or start?
Self-contained rewrite: What year did Stephen Hillenburg start teaching?