257 confirmed cases, 13 confirmed dead.
That's a 5% mortality so far. The numbers are small, so this prediction is not so accurate.
As far as I know, the 1918 flu had a mortality rate of 2.5-5%, and infected nearly the entire population of the world. This means about 100 million people died.
But in 1918, while the war was raging, the British officers just thought it was a harmless flu, and did not have any preparation. It seems we are a lot more prepared now though.
Whatever happens in the next few days could have a massive influence on the number of deaths. If the flu can be contained before it mutates again then it can be stopped. If not, then it will spread exponentially, through birds, humans and pigs, and the only safe place on the earth will be Madagascar.