As a couple of people have pointed out, human hearing ranges from 10 Hz to 10,000 Hz, but as people get older and as they damage their hearing by listening to very loud music, firing guns without ear protection, working in very noisy environments or having other physical damage, that upper end drops off. At 64 yrs old, with a long history of a target shooter before we thought about ear protection, and after many years as a rock and roll disk jockey.