Ten days ago I was riding my mountain bike into work when, thinking excessively about rattlesnakes due to a spat of recent news stories, I paid less attention than I should have and soon found myself tumbling over my handlebars. I landed hard on my left shoulder followed by my head which hit the ground fairly hard also. (I was wearing a helmet.) For the better part of a week I could barely lift my left arm, my back hurt, and I had low-level headaches and difficulty, it seemed, recalling names. I felt old. A day later I got an e-mail from my high school friend Lara, informing us that a classmate was very ill with recurrent cancer. He died four days later. In an exchange of e-mails many of my friends reflected on death and our mortality.
In one forwarded e-mail a classmate wrote “I still find it hard to believe that we have lost so many of our classmates at such young ages, and so many tragic ways.” I was a little taken aback by that. Had many of my classmates died? I confess that I’m somewhat out of touch with my high school class. I only attended our 5 year anniversary, and since I’ve spent the majority of my adult life far away from Utah my intersection with classmates to get updated on the happenings of others had been sparse. Except for Anne Jahries Sleater who had been shot and killed by a mentally ill woman, I couldn’t recall another death.
With a little help from Google, I found the 2007 Life Period table published by the Social Security Administration and proceeded to estimate how many of my classmates would be expected to be deceased by now. Of 100,000 live male births, 98754 would be expected to be alive at age 18 (graduation), and 94800 would be expected to be alive at age 43 (present). That means that about 4% of my male class should have already passed away. The numbers are better for female classmates, of whom slightly less than 2% should have died. Assuming a 50/50 class of 400 students, about twelve of our classmates should have died by now.
During a phone call with a friend I mentioned that we’re getting close to the age where death won’t be so rare among us anymore. That, thankfully turns out to be somewhat of an exaggeration. Our annual probability of death for the next year is still under 0.3%. And looking at the published survival curve below, it seems we’ve got another twenty years before we hit the knee of the curve. Following the 1900 curve, it is easy to appreciate how different our lives are now than those of our grandparents or great grandparents: we may be losing some classmates, but few of us have lost our children.