Some back-of-the-envelope maths regarding Luis Suarez: according to Wikipedia, he has played in 363 club league, cup and friendly matches since breaking through into the Nacional senior team in the 2005/06 season. He's also played 78 times for the Uruguay national team.
He has bitten three opposition players in the time it took him to play those 441 senior matches – PSV's Otman Bakkal in November 2010, Chelsea's Branislav Ivanović in April 2013, and now Italy's Giorgio Chiellini in the World Cup game on 24 June. This raises a crucial question: how much risk is a football player taking if Luis Suarez is on the opposition team? You’ve got to know the risks when you get involved in a contact sport, after all.
Let's crunch some numbers. Suarez’s bite rate of three in 441 means we can expect him to take a bite out of someone every 147 matches, but if we assume that there are 14 players at risk of being bitten (that's 11 starting players and assuming three substitutes come on) that means Suarez has bitten three players out of the 6,160 who have lined up against him in his professional career.
We can therefore conclude that Luis Suarez has roughly a one in 2,000 chance of biting any individual opposition player. For comparison, the following things are less likely than being bitten by Luis Suarez:
- Bitten by a shark while swimming in the ocean (one in 3.7 million)
- Struck by lightning once across an 80 year lifespan (one in 10,000)
- Dying from a hornet, wasp or bee attack (one in 75,852)
- Being killed by a firearm in the United States (one in 6,509)
- Living on a coastline and experiencing a tsunami (one in 50,000)
- Hit by an asteroid (one in 700,000)
And, conversely, the following things are more likely than being bitten while playing against Luis Suarez:
- Dying on a space shuttle mission (one in 100)
- Getting cancer (between one in two and one in three for any kind)
- Experiencing some or any symptoms of concussion after a soccer match (one in two)
- Having an ear bitten off by Mike Tyson during a boxing match (one in 50)
UPDATE: OK, as many people have pointed out, it's unreasonable to compare the 1/2000 chance for a professional player on the pitch facing off against Suarez to the shark attack chance, as it's an average of shark attack fatalities - not all attacks, only fatalities - for the entire United States (including lots of places where shark attacks never happen). Better to compare to a place where sharks live, and a swimmer is more likely than not to be in the water within a short distance of a shark: New Smyrna Beach, Florida.
A popular tourist and surfer destination, it has been called the "shark attack capital of the world" and has dozens of attacks per year - most of which are "nibbles" rather than life-threatening. The Global Shark Attack File has records of four attacks in the half year so far in 2014; the town's population was 22,464 as of the 2010 census. Assuming everyone in the town goes for a swim in the ocean at least once per year (or that it averages out to be effectively 22,464 swimmers per year), that gives us a figure of one in 2,808 swimmers getting bitten this year. New Smyrna Beach's record for the number of bites in a year is 28 in 2008; that would give us one in roughly 800 swimmers being bitten. The average is likely somewhere in the range between the two figures.
This means that Luis Suarez is almost exactly as likely to bite someone as a shark is in the very definition of "shark-infested" waters.