Jesus, this would be an issue IF and ONLY IF the rest of those 150k people were on their way out, but they aren't, its 50 dead and 149,950 going on to survive and being immune to it. This isn't a rising percentage of deaths, and theres a limit to how many people can die when the MASSIVE MAJORITY ARE BECOMING IMMUNE after having it.
As for a variant of the pnuemonic plague, jesus h christ, firstly it was bubonic plague that was responsible for most deaths, the pneumonic version was primarily simply caused by bubonic plauge spreading to the lungs, the only real difference is the location. Its a bacteria and has utterly nothing to do with Swine Flu, pneumonia on its own, isn't pnuemonic plague, its just a basic infection(or one of several other infections) that also simply spread to the lungs and are reclassified essentially.
Scaremongering, like the OP, doesn't help anyone, stop making up added information and talking about how serious it is, when it isn't, more people will die from it, so, more people will die from the normal flu aswell, and from old age, cancer, car crashes, murders, etc, etc. People die every single day, thousands, and thousands every single day of your life 50 out of 150k is nothing.
THe most easily infected are those already ill, who are the most likely to die from secondary complications with swine flu, so the earliest to get it have the highest death rate, as more people get infected it will be the less immune comprimised and less likely to die.
Early numbers will always be the worst due to the nature of who gets infected first.