Simplify the following text for a Grade 8 native English-speaking person.
Original: Waldheim was the fourth Secretary-General of the United Nations from 1972 to 1981 , and the ninth President of Austria , from 1986 to 1992 .
Simplified: He was Secretary-General of the United Nations from 1972 to 1981 , and President of Austria from 1986 to 1992 .