FlowingData has a depressing post about how your probability of death increases as you get older. A 20 year old male has about a 0.13% chance of dying in the next 12 months, while by 60 it’s up to 1.23%, and at 70 you’re looking at 2.89%.

However, the data (for the US) can be presented a different way. Suppose we add your current age to your remaining life expectancy. This gives your expected age at death as a function of your current age:

The interesting thing about this graph is that it’s upward sloping — getting older is good news in the sense that it increases the age at which you can expect to die. When you’re born, you can expect to live until about 74 if you’re male and about 80 if you’re female. If you make it to 60, these increase to 80 for male and 83 for female. Make it to 80 and you can expect to hit 87 if you’re male or 89 if you’re female. The reason is that the people remaining alive at 80 have proven themselves to have above-average health.

We can also calculate the marginal increase in expected age of death that you get at each birthday:

You can see that making it to your 1st birthday increases your expected age of death by about half a year. After that, the returns aren’t so great until you hit 50. Then each birthday you have increases your expected age of death significantly. Your 50th birthday gives you about an extra 2 months, and your 80th gives you a whole extra 6 months.

So birthdays really are something worth celebrating …