Normal puberty is characterized by a growth spurt, after which growth slows then stops at the final adult height. Boys typically begin growing rapidly at about 11 years of age, growing at a peak rate of about 9.5 centimeters per year. Girls begin rapidly growing at about 9 years of age, reaching a peak growth velocity of about 8.3 centimeters per year. Pubertal growth accounts for 17-18% of the final adult height in males and females.