The first problem is already revealed in the question. Sharks are basically not dangerous. Only circumstances may lead to situations that are potentially dangerous for humans. Now many people may feel this is splitting hairs. But there is a big difference between animals that are considered dangerous and certain situations that may be potentially threatening.
Many situations pose no threat whatsoever to humans, even though a large shark may be swimming around. The dangerous shark is just as rare as the non-aggressive shark. Obviously, there are species which - simply due to their size - should only be approached with great caution, for body size is a problem when it comes to dealing with sharks. Still, even though most sharks shown on television or in aquariums are mostly imposing in size, it must be emphasized that of the over 460 shark species only a small fraction of them grow so large as to cause serious injuries to people. Most are much too small to accomplish this. However, size alone only plays an indirect role. Much more important is the fact that many large species of sharks seek prey whose size is comparable to that of human beings.
To attack their prey, sharks inevitably need the respective "tools". Undoubtedly, shark teeth can cause serious wounds on humans. However, these teeth were developed amidst a natural environment unrelated to humans to guarantee survival in the natural environment. Yet human beings often tend to view nature and its inhabitants from a very narrow-minded, anthropocentric perspective which may completely overshadow the true circumstances. The genuine danger is not the mere presence of sharks but rather the fact that the size of people who find themselves in the ocean clearly falls into the spectrum of prey sought by large-sized sharks.
The root, or imminent danger, is then controlled by the shark's inhibition threshold which prompts him to either approach an unfamiliar "object" or avoids it. The inherent danger is thus not the animal itself but rather the fact that by virtue of his size, man fits perfectly into the shark's range of prey, that humans spend time in areas where sharks live and hunt, and that sharks cannot analyze and eliminate us from their normal palette of prey.
But does this really mean that a shark practically always bites without having been provoked beforehand? That is exactly what statistics such as those stemming from the ISAF would like us to believe. The fact is, however, that when analyzing the situation in greater detail, the victims usually put themselves into situations, or already found themselves in situations that sharks find challenging or provoking and which prompt their reaction.