In very wealthy PSEland, the hourly rate is £1,000. A man works for 1,000 hours and earns £1,000,000. Nice going!
The next year, the government of PSEland decided to raise his wages by 10%, so to earn his million, he only worked for 909.090909 hours, which is 91% of 1000 hours (roughly!).
So a 10% increase in wages results in a 9% decrease in worked hours.
Where did the 1% go?