Question: What worldwide ranking does Javier Barros Sierra's employer hold?

Knowledge 1: Javier Barros Sierra
Born in Mexico city, he studied civil engineering at UNAM. He became president of the student society of the Faculty of Sciences in 1936 and University Counsellor in 1938. He taught for more than 20 years in the Escuela Nacional Preparatoria (a high school of UNAM) and the National School of Engineering (later Faculty of Engineering), of whom he was director from 1955 to 1958. He became Rector on May 5, 1966. During his rectorship, the government and the army entered Ciudad Universitaria, UNAM's main campus. In protest of these actions and the indiscriminate beating of UNAM's students, he resigned his post on September 23, 9 days before the massacre in Tlatelolco. He was reinstated as Rector after the liberation of CU, a post he held until May 5, 1970. [SEP] Knowledge 2: Mexico City
The National Autonomous University of Mexico (UNAM), located in Mexico City, is the largest university on the continent, with more than 300,000 students from all backgrounds. Three Nobel laureates, several Mexican entrepreneurs and most of Mexico's modern-day presidents are among its former students. UNAM conducts 50% of Mexico's scientific research and has presence all across the country with satellite campuses, observatories and research centres. UNAM ranked 74th in the Top 200 World University Ranking published by Times Higher Education (then called Times Higher Education Supplement) in 2006, making it the highest ranked Spanish-speaking university in the world. The sprawling main campus of the university, known as Ciudad Universitaria, was named a World Heritage Site by UNESCO in 2007.
Knowledge 1: Javier Barros Sierra
Javier Barros Sierra (1915-1971) was a Mexican engineer and Rector of the National Autonomous University of Mexico during the 1968 Tlatelolco massacre. [SEP] Knowledge 2: Mexico City
The National Autonomous University of Mexico (UNAM), located in Mexico City, is the largest university on the continent, with more than 300,000 students from all backgrounds. Three Nobel laureates, several Mexican entrepreneurs and most of Mexico's modern-day presidents are among its former students. UNAM conducts 50% of Mexico's scientific research and has presence all across the country with satellite campuses, observatories and research centres. UNAM ranked 74th in the Top 200 World University Ranking published by Times Higher Education (then called Times Higher Education Supplement) in 2006, making it the highest ranked Spanish-speaking university in the world. The sprawling main campus of the university, known as Ciudad Universitaria, was named a World Heritage Site by UNESCO in 2007.
Knowledge 1: Javier Barros Sierra
Javier Barros Sierra (1915-1971) was a Mexican engineer and Rector of the National Autonomous University of Mexico during the 1968 Tlatelolco massacre. [SEP] Knowledge 2: Javier Barros Sierra
Born in Mexico city, he studied civil engineering at UNAM. He became president of the student society of the Faculty of Sciences in 1936 and University Counsellor in 1938. He taught for more than 20 years in the Escuela Nacional Preparatoria (a high school of UNAM) and the National School of Engineering (later Faculty of Engineering), of whom he was director from 1955 to 1958. He became Rector on May 5, 1966. During his rectorship, the government and the army entered Ciudad Universitaria, UNAM's main campus. In protest of these actions and the indiscriminate beating of UNAM's students, he resigned his post on September 23, 9 days before the massacre in Tlatelolco. He was reinstated as Rector after the liberation of CU, a post he held until May 5, 1970.

Answer: 74th