Call it Longevity Angst. After thousands of years in which human life was "nasty, brutish, and short," survivors of The Alienated Century have a new worry. Today we wring our hands about "living too long." Of course, no one is very precise about when we will have lived too long. Generally, it is not today, tomorrow, or next week. It is sometime in the distant future.

For some, it is when they run out of money.

The concern is no surprise: By the time we've turned 60 we've probably spent at least 40 years worrying about running out of money. Then, if we've been diligent savers and investors, we can worry about something else--- running out of mind, body, or both.

As Gilda Radner said, "It's always something."

But let's get back to the fun worry.

We'll never know exactly how long we'll live, but we can measure the ballpark of life and death by studying what happens to large groups of Americans. That's one of the things they do at the Centers for Disease Control and Prevention. The table below is part of a life table for all Americans, which was produced in 2002. Life expectancies have continued to improve since then, so the table can be viewed as slightly conservative.

The full table, called a period life table, starts with 100,000 individuals at birth. It follows them year by year. It tells us how many are likely to die in any given year of life. It also tells how long the survivors can expect to live. Each year the number of survivors is smaller so the whole table looks a bit like the famous Charles Joseph Minard graphic depicting Napoleon's invasion of Russia and his retreat.

Many started, but few returned.

In fact, the life table contains a lot of good news. For one thing, 85,911 of the original 100,000 survive to age 62. And 82,607 survive to 65, the traditional retirement age. That means most Americans--- at least 85.9 percent of them--- have a future well beyond their working years.

If we take a closer look and start clocking survival from age 62, we find that 87.7 percent of those who live to 62 will live long enough to start taking Required Minimum Distributions from their IRA accounts at age 70.

Ten years after that, at age 80, six out of ten will still be alive. And they will still be expected to live another 8.8 years.

The next ten years, from 80 to 90, are tough because two out of three who survived to 80 will be dead by age 91. Four out of five who lived to 62 will have passed on. Aging--- real aging--- isn't for sissies.

Optimal Ages to Claim Social Security Benefits
This table shows the retirement ages at which a couple is likely to achieve maximum lifetime Social Security benefits.
Age Difference	Wifes' earnings 0-30 percent of husband's	Wife's earnings 30-40 percent husband's	Wife's earnings 40-100 percent husband's earnings
0 years	66 husband, 66 wife	67,66	69,62
3	68,65	69,62	69,62
6	68,62	69,62	69,62
Percent of households	32.1	11.0	47.2
Source: Alicia H. Munnell and Mauricio Soto, Center for Retirement Research

This table is for all Americans, but some identifiable groups will do significantly better than others. Women will live longer than men. White people will live longer than black people. Black women will live longer than white men. A 62-year-old white woman can expect to live 21.9 years while her 65-year-old husband can expect to live only 16.6 years, which means she can, typically, expect to be widowed for 5.3 years.

None of this is cast in stone, of course. But this is our collective profile, and it has improved for more than a century.

On the web:

Charles Joseph Minard's graphic display of Napolean's 1812 campaign