The phrase "average lifetime" is correct and can be used in written English.
You might use it to describe the length of time something typically lasts: "The average lifetime of a car is approximately 15 years."
It talks about "average" lifetime contributions, pension expectations and post-retirement nest-eggs.
He is 5-0 with a 1.73 earned run average lifetime against the Twins.
In an average lifetime, he will produce two thousand billion sperm.
(In the general population, the average lifetime risk of ever developing Alzheimer's is about 10percentt).
(The average lifetime risk for women in the United States is 12percentto13percentcent).
S.S.D.I. payments are calculated according to a person's average lifetime earnings before he became disabled.
Mean life, in radioactivity, average lifetime of all the nuclei of a particular unstable atomic species.
That makes 243 hours a year, or more than a full year in an average lifetime.
Up to four hours a day in England, which adds up to nine years over an average lifetime.
Figure 9 Average lifetime of nodes.
The average lifetime was indicated in each mapping images.
