I reportedly have about 4% Neanderthal genes. That's just a little more than the mean for European ancestry.
Which is, roughly, the kind of percentage you would get from having a great great great grandparent who is a fullblooded Neanderthal.
The percentages of average shared DNA lay out like this:
3.125% great great great grandparent
6.25% great great grandparent
12.5% great grandparent
Troglodytes in the family tree,
And back, before that, a chimpanzee!
Such descriptions are inexact,
But rhyme exactly - that's a fact!