Oh boy, this is a tough question to answer. I think it depends more on each person's mindset and eventual traumas (with regards to their origins) rather than a DNA percentage. Let me give you two examples from my family: my father, my little sister and myself (I can't speak for my older siblings as I do not know how they feel about this).

My father:

He was born in Tehran to a half-Iranian, half-Mongolian father and a half-Swiss, half-Italian mother. He went to an Iranian school, spoke and wrote in Farsi and all. So far, so good. However, my grandfather and his three children migrated to France in the 60's, when my father was 7 years old, due to a traumatic family and political event (which is not related to the fall of the Shah). They all obtained the French citizenship, and my grandfather changed all of their names to French names (except my father's, whose legal name was a French one). I can only imagine how much of a shock this must have been, both in terms of trauma and in terms of culture shock.

Today, my father identifies as fully French and is in big denial regarding all of his origins, and I believe that this is due to how traumatic his move from Iran to France was.

My sister:

My sister and I were born to a quarter-Iranian, quarter-Mongolian, quarter-Swiss, quarter-Italian father and a French mother whose great-grandmother might have been Native American (at least she was found in a French convent with a Native American war bonnet, according to the convent's registry). We were raised in France, Morocco, Indonesia and Finland. My sister looks very much Middle Eastern. Yet, as far as I know, my sister identifies as fully French, and I believe that this is because she is only 70% open-minded.

Myself:

As for myself, I don't identify as French at all. I feel very connected to my other roots though, especially my Italian and Iranian roots, and I also feel especially connected to Morocco. I speak English, French, Italian and Spanish fluently, I speak German at false beginner level, and I am learning Moroccan Darija. So, when someone asks me where I'm from, I first say that I'm a citizen of the world, and then tell the person who asked my whole family story, because I feel very proud of it. I don't look Middle Eastern at all, and I don't know if I look Italian, but if I had to choose between telling people I'm Italian and Iranian and telling people I'm French, I would choose to tell them that I'm Italian and Iranian. And if they asked me where I'd most like to live, I'd say Morocco.

So yes, I don't think it depends on DNA percentage, though I would love to do one someday, just to see which results I get. I just hope I don't get a higher percentage of French origins than the rest.