Final answer:
The question seems to be asking for a specific percentage to describe an even mixture of gray and pigmented hair, which is not directly provided in the information. However, an even mixture could be interpreted as about 50%, considering how semi-permanent hair dye blends gray and pigmented hair.
Step-by-step explanation:
The percentage that would represent an even mixture of gray and pigmented hair is not explicitly stated in the information provided. Hair color changes due to the levels of melanin in the hair follicles, which can decrease with age, leading to graying hair. When it comes to hair coloring, semi-permanent dyes might not completely cover gray hair, leading to an even mixture of pigmented and non-pigmented hair over time. This eventual blend could be interpreted as the hair containing equal amounts of both types, potentially around 50%.
Understanding the coloring process is essential, particularly when using semi-permanent colors, as these will wash out after four to six weeks and are less harsh than permanent dyes. Moreover, the underlying original color and porosity of the hair affect how the dye is absorbed, which therefore influences the final appearance, including how grays are blended.