 1972 , it was estimated that 24 % of American women wore shoulder length hair or longer ( 44 % of women in ages 14 to 44 ) , meaning slightly more than 12 % of men and women altogether . Similar frequency was found in 2001 , when it was estimated that about 13 % of the US adult population , male as well as females , has hair shoulder @-@ length or longer , about 2 @.@ 4 % have hair reaching to the bottom of the shoulder blades or longer , about 0 @.@ 3 % have hair waist length or longer , and only about 0 @.@ 017 % have hair buttocks @-@ length or longer . By extrapolating the above data and the number of hair length records , the number of people with waist length hair in USA is estimated to 27 million , with buttocks @-@ length hair to 40 @,@ 000 , with knee length hair to 2 @,@ 000 and with ankle length hair to 70 . 
