I already told you.
How does the change affect fitness?
Obviously, the mutation makes no change in fitness. It is called neutral.
That's all there is.
There is an observed change in the phenotype but no change in fitness, is that what you are saying?
I am not aware of any specific technical name for the concept "mutation that does not change protein" except "neutral."
Which is exactly how I was using the term which caused all this brouhaha for no purpose apparently.
There was another brouhaha not long ago about some other supposed misuse of terminology I was guilty of, I hope it will come back to me, because while reading through some threads I discovered one of your very own using that term in the very same sense I was using it. I meant to post on that, got distracted I guess. I hope I remember it eventually.
Sorry. I forgot the second part of your post. Are mutations that do not change proteins the most common type?
Neutral mutations are the most common type.
What percentage of these involve protein changes or not, or happen in non-coding regions or do change phenotype with no affect on fitness, I don't think anyone knows.
Neutral mutations with respect to fitness then is what you are talking about. But obviously if there is no change in phenotype you are looking at the DNA and calling mutations at that level "neutral" but how can they be "neutral with respect to fitness" if you see no change in the phenotype anyway? So you see mutations at the DNA level and call them "neutral" although you see no change whatever in the phenotype. I'm sorry, I know I'm not getting this question asked clearly, but there's something odd about your statement, like it implies switching back and forth from DNA level observation to phenotypic observation but not making a change in the terminology with respect to fitness. Sorry, I'm tired. If you can make sense of this please answer it but I have to get some sleep.