There are approximately 370 known species of fish within the shark family, ranging in size from the 15cm Squaliolus Laticauda' to the 15m Whale shark, the worlds largest fish.
For all their reputation only 35 species have ever been known to attack humans and virtually all known incidents involve less than ten species with the Great White, Tiger and Bull sharks top of that list.
It's interesting to note however for every person killed by a shark over 23,000 tonnes (!) of sharks / rays are killed through commercial or recreational fishing!