Given this paragraph about Mohamed Fourati, at what age was he appointed as hospital assistant?

Context: A year after getting his philosophy baccalaureate in his native town Sfax, Mohamed Fourati moved to Lille to pursue his graduate education in the medical school of Lille. In order to validate his studies, he became an intern in the Farhat-Hachad Hospital of Sousse. Traveling between the two continents, he secured, in 1959, a medical doctorate at the medical school of Lille. He performed his military service, the following year, in the region of El Kef and in Kébili. He continued to specialize in thoracic and cardiovascular surgery at the Saint-Joseph Hospital of Paris. He got assigned to the general surgery unit of doctors Saïd Mestiri and Zouhair Essafi at the Habib-Thameur Hospital in Tunis. In 1961, over the month of July, he worked as a surgeon in the battle of Bizerte, performing surgery on patients 20 hours a day for many days. He got appointed as hospital assistant in 1966, then earned the title of chief physician of the surgical ward in the Habib-Thameur Hospital in May 1968 and became, at the age of 35, the youngest chief physician in Tunisia. In November of the same year, he performed the first open-heart surgery, favored by a delegation of doctors of the IFTHD.

Answer: He was appointed hospital assistant in 1966. In 1968, he was 35 years old. So in 1966, he was 33 years old.