Simplify the following text for a Grade 8 native English-speaking person.
Original: Tracy killed 71 people , caused $ 837 million in damage ( 1974 AUD ) and destroyed more than 70 percent of Darwin 's buildings , including 80 percent of houses .
Simplified: Tracy killed 71 people , caused $ 837 million in damage ( 1974 AUD ) and destroyed more than 70 % of Darwin 's buildings , including 80 % of the houses .