Stats, eh?
In all the 72 F1 races Jim Clark raced in, he was on pole position in 33. He got 8 grand slams (pole position, fastest lap, led every lap, won the race) out of his 72 races; next on the list is Lewis Hamilton, with 6 grand slams from 335 races.
He won 70% of all races in 1963. He won the Belgian GP by nearly 5 minutes, still a record.
He still holds a few records, 60 years after he was at his peak. Other champions (Senna, Stewart) considered him the best ever.