Can we draw the following hypothesis from the context? 

Context:

Sherwood Stewart (born June 6, 1946, in Goose Creek, Texas, United States) played amateur and professional tennis in the 1970s and 1980s. Stewart was ranked as high as No. 60 in the world in singles on the ATP Rankings on December 31, 1978, and No. 4 in doubles on January 3, 1983.

Hypothesis: Stewart was ranked as number 60 in the world of singles in 1978 and in 1980/
No