As I was putting together the article about America's future demographics, I showed the last chart to a colleague.

"Whoa," she responded. "Teen death." That's a bit strong, but the point is an interesting one: By 2050, teens (does that need a hashtag?) will make up a small percentage of the population. But then I looked at the long-term trend and discovered something alarming.

There are currently fewer #teens as a percentage of all Americans than at any point on record. And it will keep dropping.

(Universal Pictures)

Here's the total number of 13-to-19 year olds over the past 50 years. (The most recent data from the Census Bureau is an estimate from 2013.)

Up and down and up again. The most recent up is the so-called Millennials. In general, it's pretty flat, thanks to the dropping birth rate.

The problem for teen density is that the rest of the country keeps getting older and the population keeps growing. Meaning that the percentage that is #teen keeps getting lower.

Since the number of #teens ebbs and flows, so does the percentage of Americans that are teens. It's at a low for the past 50 years ...

... but it's also at a low since 1900. The previous low came in 1953, when the babies of the Baby Boom hadn't yet hit their teenage years.

Before 1900, the percent of the country that was #teen was almost certainly higher -- since American life expectancy wasn't as long. Fewer old people means that young people make up more of the population.

There are still #teen pockets. Out west, there are more #teens, thanks to high birthrates among Mormons and Hispanics.

In general, though: crisis.

Can American culture survive this #teen #crisis? Let's look at it another way: We have more #teens per capita right now than we're likely to for decades. Let's make the most of it.