Can you imagine that Blond is just  a hair color characterized by low levels of the dark pigment eumelanin.
I'm Blonde! whats the percentage of blondes to dark haired individuals?
percentages I am really not sure but I can tell you that your blond is always has some sort of yellowish color.
What about the eye color pigment? is that always blue or can it change?
It definitely causes by the same thing pigment deficiency buddy, The word "blond" is first documented in English in 1481 
Who was the founder?
Old French "blund, blont", meaning "a colour midway between golden and light chestnut". It gradually eclipsed the native term "fair", of same meaning, from Old English "fæġer", causing "fair" later to become a general term for "light complexioned". This earlier use of "fair" survives in the proper name Fairfax, from Old English "fæġer-feahs" meaning "blond hair".
The word "blond" has two possible origins. Some linguists say it
Blond
Blond or fair hair is a hair color characterized by low levels of the dark pigment eumelanin. The resultant visible hue depends on various factors, but always has some yellowish color. The color can be from the very pale blond (caused by a patchy, scarce distribution of pigment) to reddish "strawberry" blond or golden-brownish ("sandy") blond colors (the latter with more eumelanin). Because hair color tends to darken with age, natural blond hair is generally rare in adulthood. Naturally