Complex sentence: Of the 24 all-time best high jumps, 17 are his; he cleared 2.40 meters more times (17) than any other athlete and is the only person to have cleared 2.44m (8 ft) (which he did twice).
Split into simpler sentences: Of the 24 all-time best high jumps, 17 are his. He is the only person to have cleared 2.44m (8 ft) (which he did twice).