Only 2% of the world's population has naturally blonde hair.
However, it is much more common for a young person to have blonde hair as a child and then it turns darker over the years. If you had blonde hair as a child (and it has probably now turned darker to a brown or light chestnut color), you are considered blonde - you will have light eyebrows and eyelashes.
It turned out that the darkening of blond hair in children is a completely natural process, and only a small number of them retain the same color. Most people's hair darkens during preschool or during the transition period.
If you are looking at childhood photos in your photo album and have a question about why you no longer have Barbie-like blond hair, as before, the reason is simple and the answer is genetics. Yes, genes affect the regulation of the color pigment.
There are two types of melanin pigment: eumelanin and pheomelanin. The higher the concentration of eumelanin, the darker the hair color. If the amount of pheomelanin in the body exceeds, you will find yourself in the small number of people in the world who, despite increasing age, have not lost their natural blond hair color.
Let's not blame genetics alone and take into account environmental factors, in particular, artificial lightening and chlorine damage the structure and color of hair.
Source:
https://www.celebricious.com/2020/02/why-does-blonde-hair-get-darker-with-age/
