7 hours average for anyone from 21-24 years old.
6 hours thereafter. This keeps decreasing as you get older.
about 8 to 10 hours of sleep
I'm quite sure they need at least 7 hours.
Children need 8 hours.
9 - 10 hours
8 - 10 hours.
Depends on the length of your "sleep cycles", but generally 7-9 hours.
10-11 hours every night are the optimum hours of sleep an eight-year-old should get.
if you mean how many hours you should sleep in a year it would be 3,650 hours of sleep for a regular year not a leap year