English-Chinese/Graying is a gradual process

Graying is a gradual process; according to a study by L'Oreal, overall, of those between 45 and 65 years old, 74% had some grey hair, covering an average of 27% of their head, and approximately 1 in 10 people had no gray hairs even after the age of 60.

头发变白是一个渐进的过程; 根据L'Oreal的一项研究，总体而言，在45至65岁之间，74％的人有一些白发，平均占头部的27％，大约十分之一的人甚至60岁之后也没有白发.