A set of mortality rates by age – usually spanning ages 0 to 120. The table will usually represent the pattern of mortality experienced by age for a specific group of individuals – with the experience having been smoothed to form a gradual progression of mortality with age. The rates will typically fall over the first few months of life before increasing with age. An exception to this is the period during late teenage years and early twenties when boys (but to a growing extent girls as well) experience a number of years of heightened mortality. This extra mortality is largely due to the risks of the testosterone fuelled years of late youth / early adulthood - cars, alcohol, etc - hence it is known as the ‘accident hump’.