Complex sentence: He was a regular contributor to Sports Illustrated since its first month of publication in 1n 1954 he published more than 1,200 of his editorial drawings and more than 200 of his promotional and advertising drawings.
Split into simpler sentences: He was a regular contributor to Sports Illustrated since its first month of publication in 1n 1954. During his career, the magazine published more than 1,200 of his editorial drawings and over 200 of his promotional and advertising drawings.