Quirks of statistics. To have an average of 4.5, you need people to die before and after the mark. So a lot of people drop off between 91 and 92. But those wh

Quirks of statistics. To have an average of 4.5, you need people to die before and after the mark. So a lot of people drop off between 91 and 92. But those who make it to 92 have about 4.2 years remaining. If you have a population of 100 people and 50 of them will live less than 1 year, and 50 of them will live an average of 10 years, that's 5.5 years on average for the whole population. But if you check that same population one year later, you will have 50 people who all live 9 years on average. You've managed to increase the average by eliminating the bottom. Same thing is happening here. And it's probably similar to professional sports careers. The average NFL career is about 3 years. However, if you make to 3 years, your average career length is about 7 years. We probably need more of a median or mode than a mean.