Is Necrotizing Fasciitis Common or Rare?

I've been reading about this girl that after an accident she got the flesh eating bacteria and I was wondering if this necrotizing fasciitis is common or rare? This is the first time I hear about something like necrotizing fasciitis but it doesn't sound so good, so, if someone can answer this I'd truly appreciate it.
This girl got the bacteria in the water and I live near a lake so I don't want to get necrotizing fasciitis myself, not even know if it's curable.

Hello, first of all don't worry about necrotizing fasciitis because it's not so common, it's not like you can catch up in the supermarket like a flu. It's really a rare disease but deadly as well. So, you need to know that if any symptom of necrotizing fasciitis shows up, just go to the nearest hospital to get early treatment.
Although it's not common and it's defined by many doctors as rare, it still exists and there are many reported cases of flesh eating bacteria. Just avoid getting hurt in the water.