I'm actually pretty disgusted that decimation has such a bad reputation. People say "oh they were decimated" and make it sound like there were no survivors. The word itself comes from Latin and essentially means 1 in 10.
Don't believe me? Read the wikipedia article about it. Don't believe them? Take a time machine back to ancient Rome and ask around.
So decimating means that every one in ten is destroyed. Which leaves you with a 90% survival rate. So if the news tells me a plague is going to decimate society... I'll take my chances.
It's when things are going to be bimated that you need to be worried.