Phases of stuttering?

Phases of stuttering? I’ve had a stutter for as long as I could speak and as I’ve gotten older, I’ve noticed years of my life where my stutter was severe and years where it wasn’t present at all. Like my 4th and 8th grade school years I had no problem speaking, but almost every year besides those has been either a slight stutter or incredibly severe stutter. Is this common? I’ve noticed my stuttering is usually attributed to my level of anxiety so maybe it was a developmental thing where those were simply the years where I was less anxious in my life? Idk.