Older people are much more likely to carry the mites; about a third of children and young adults, half of adults, and two-thirds of elderly people carry them. The lower rate in children may be because children produce less sebum. A 2014 study of "n" = 29 people in North Carolina, USA, found that all the adults ("n" = 19, over 18 years of age) carried mites, and that 70% of those under 18 years of age carried mites. This study (using a DNA-detection method, more sensitive than traditional sampling and observation by microscope), along with several studies of cadavers, suggests that previous work might have underestimated the mites' prevalence. The small sample size and small geographical area involved prevent drawing broad conclusions from these data.